A simple review and study guide for Medical Laboratory Technician (MLT) examination for Clinical Chemistry.
Source: ASCP (BOR) Book
| MLT Boards- Chemistry (BOR) | |
|---|---|
| Questions | Answers |
| The urinary excretion product measured as an indicator of epinephrine production is: | vanillylmandelic acid |
| Which 2 conditions can "physiologically" elevated serum alkaline phosphatase? | growth, third trimester of pregnancy |
| The T3 resin uptake test is a measure of: | binding capacity of thyroxine-binding globulin |
| During an evaluation of renal function, a patient had plasma cortisol determinations in the morning after awakening and in the evening. Laboratory results indicated that the morning value was higher than the evening concentration. This is indicative of | a normal finding |
| In the liver, bilirubin is converted to: | bilirubin diglucuronide |
| The results listed on page 120 were obtained in a creatinine clearance evaluation: The creatinine clearance in mL/min is: | 65 |
| The electrophoretic pattern of plasma sample compared with a serum sample shows a: | sharp fibrinogen peak |
| The biuret reaction for the analysis of serum protein depends on the number of: | peptide bonds |
| Total iron-binding capacity measures the serum iron transporting capacity of: | transferrin |
| In the Jendrassik-Grof method for the determination of serum bilirubin concentration, quantitation is obtained by measuring the green color of: | azobilirubin |
| Absorbance (A) of a solution may be converted to percent transmittance (%T) using the formula: | A = 2 - log%T |
| Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are both elevated in what disease? | viral hepatitis |
| Calcium concentration in the serum is regulated by: | parathyroid hormone |
| What steroid is an adrenal cortical hormone? | corticosterone |
| Blood PCO2 may be measured by: | calculations of blood pH and total CO2 concentrations |
| In the potentiometric measurement of hydrogen ion concentration, reference electrodes that may be used include: | silver-silver chloride |
| In a spectrophotometer, light of a specific wavelength can be isolated from white light with a(n): | diffraction grating |
| The osmolality of a urine or serum specimen is measured by a change in the: | freezing point |
| Which of the following serum constituents is unstable if a specimen is left standing at room temperature for 8 hours before processing? cholesterol, triglyceride, creatinine, or glucose | glucose |
| A urine screening test for porphobilinogen is positive. The MOST likely disease state is: | acute porphyria attack |
| In electrophoretic analysis, buffers: | act as a carrier for ions |
| A condition in which erythrocyte protoporphyrin is increased is: | iron deficiency anemia |
| The stimulant that causes localized sweating for the sweat test is: | pilocarpine nitrate |
| In the sweat test, the sweating stimulant is introduced to the skin by application of: | an electric current |
| The formula for calculating serum osmolality that incorporates a correction for the water content of plasma is: | 2Na + Glucose/20 + (BUN/3) |
| Osmolal gap is: | the difference between the calculated and measured osmolality values |
| Erroneous ammonia levels can be eliminated by all of the following EXCEPT: See page 124 for choices. | d. storing the specimen protected from light until the analysis is done |
| Which of the following applies to cryoscopic osmometry? See page 124 for choices. | a. The temperature at equilibrium is a function of the number of particles in solution. |
| The first step to be taken when attempting to repair a piece of electronic equipment is: | turn the instrument off |
| Most of the carbon dioxide present in blood is in the form of: | bicarbonate ion |
| The degree to which the kidney concentrated the glomerular filtrate can be determined by: | urine to serum osmolality ratio |
| How many grams of sulfosalicylic acid (MW = 254) are required to prepare 1 L of a 3% (w/v) solution? | 30 |
| A physician suspects his patient has pancreatitis. Which test(s) would be most indicative of this disease? | amylase |
| The statistical term for the average value is the : | mean |
| An index of precision is statistically known as the: | coefficient of variation |
| The most frequent value in a collection of data is statistically known as the: | mode |
| The middle value of a data set is statistically known as the: | median |
| In a specimen collected for plasma glucose analysis, sodium fluoride: | inhibits glycolysis |
| In the international system of units serum urea is expressed in millimoles per liter. A serum urea nitrogen concentration of 28 mg/dL would be equivalent to what concentration of urea? (Urea: NH2CONH2; atomic wt N = 14, C = 12, O = 16, H = 1) | 10.0 mEq/L |
| The osmolal gap is defined as measured Osm/kg minus the calculated Osm/kg. The average osmolal gap is near: | 0 |
| To be analysed by gas liquid chromatography, a compound must: | be volatile or made volatile |
| The solute that contributes the most to the total serum osmolality is: | sodium |
| In automated methods utilizing a bichromatic analyzer. dual wavelengths are employs to: | minimize the effect of interference |
| What electrode ID is based on the principle of amperometric measurement? | PO2 electrode |
| One international unit of enzyme activity is the amount of enzyme that, under specified reaction conditions of substrate concentration, PH, & temperature, causes utilization of substrate at the rate of: | 1 micromole/min |
| The Porter-Silber method (phemylhydrazine in alcohol and sulfuric acid) involves which part of the steroid molecule? | dihydroxyacetone side chain |
| Which family of steroid hormones is characterized by an unsaturated A ring? | estrogens |
| Which of the statements on page 127 about immunoassays using enzyme-labeled antibodies or antigens is correct? | c. Quantitation of the label can be carried out with a spectrophotometer. |
| What chemical determinations may be of help in establishing the presence of seminal fluid? | acid phosphatase |
| What serum protein fractions is most likely to be elevated in patients with nephrotic syndrome? | alpha-2 globulin and beta globulin |
| What enzyme substrates for prostatic acid phosphatase determination results in the highest specificity? | thymolphthalein monophosphate |
| The results lists on page 128 were obtained on arterial blood: These results are most compatible with : | respiratory acidosis |
| Increased total serum lactic dehydrogenase (LD) activity, confined to fractions 4 and 5, is most likely to be associated with: | acute viral hepatitis |
| Regan isoenzyme has the same properties as alkaline phosphatase that originates in the: | placenta |
| Assay of transketolase activity in blood is used to select deficiency of: | thiamine |
| The substance that is measured to estimate the serum concentration of triglycerides by MOST methods is: | glycerol |
| The most sensitive enzymatic indicator for liver damage from ethanol intake is: | gamma-glutamyl transferase (GGT) |
| Refer to the illustration on page 129. This electrophoresis pattern is consistent with: | alpha-1 antitrypsin deficiency; severe emphysema |
| Patients with Cushing's syndrome exhibit: | serum cortisol concentrations greater then 15 mg/dL |
| A one molal solution is equivalent to: | a solution containing one mole of solute per kg of solvent |
| Refer to the illustration on page 130. The serum protein electrophoresis pattern is consistent with: | monoclonal gammopathy |
| Refer to the illustration on page 131. This pattern is consistent with: | cirrhosis |
| Given the results listed on page 131. This is most consistent with: | acute hepatitis |
| Given the results listed on page 132. This is most consistent with: | obstructive jaundice |
| Given the results listed on page 132; This is most consistent with: | chronic hepatitis |
| Which of the statements on page 132 about fluorometry are true? | A compound is said to fluoresce when it absorbs light at one wavelength and emits light at a second wavelength. |
| A benefit of microassays includes: | reduced reagent requirements |
| Refer to the illustration on page 133. This illustration represents the change in absorbance at 340 nm over a period of * minutes in as assay for lactate dehydrogenase. True statements about this figure include: | Non linearity after 6 minutes is due to a substrate exhaustion |
| A serum sample in the emergency room from a 42-year old man yielded the laboratory results listed on page 133. What condition might account for these values? | crush injury it the thigh |
| Uncompetitive inhibition of an enzyme reaction the: | inhibitor binds to the enzyme at the same site as the substrate |
| Kernicterus is an abnormal accumulation of bilirubin in: | brain tissue |
| Two standard deviations is the acceptable limit of error in the chemistry laboratory. If you run the normal control 100 times, how many of the values would've out of control due to random error? | 5 |
| Serum haptoglobin can be separated into: | distinct phenotypes by starch-gel electrophoresis |
| Which serum protein migrates with the beta-globulins on cellulose acetate at pH 8.6? | C3 component of complement |
| Fasting serum phosphate concentration is controlled primarily by the: | parathyroid glands |
| Serum "anion gap" is increased in patients with: | lactic acidosis |
| Increased serum lactic dehydrogenase activity due to elevation of fast fraction ( 1 and 2) on electrophoretic separation is caused by: | hemolytic anemia |
| The nanometer is used as a measure of: | wavelength of radiant energy |
| Major actions of angiotensin II include: | increased vasoconstriction |
| The presence of increased CK-MB activity on a CK electrophoresis pattern is most likely found in a patient suffering from: | myocardial infarction |
| What is the molarity of a solution that contains 18.7 g of KCl (MW=74.5) in a 500 mL of water? | 0.5 |
| In the total bilirubin assay, bilirubin reacts with diazotized sulfanilic acid to form: | azobilirubin |
| Total glycosylated hemoglobin levels in a hemolysate reflect the: | average blood glucose levels of the past 2-3 months |
| The identification of Bence Jones protein is best accomplished by: | immunofixation |
| The anion gap is useful for quality control of laboratory results for: | sodium, potassium, chloride, and total CO2 |
| What percentage of total serum calcium is nondiffusible protein bound? | 40-50% |
| The buffering capacity of blood is maintained by a reversible exchange process between bicarbonate and: | chloride |
| What electrolyte is the chief plasma cation whose main function is maintaining osmotic pressure? | sodium |
| A reciprocal relationship exists between: | calcium and phosphorus |
| A colorimetric method calls for the use of 0.1 mL serum, 5 mL of reagent and 4.9 mL of water. What is the dilution of the serum in the final solution? | 1:100 |
| At blood pH 7.40 what is the ratio between bicarbonate and carbonic acid? | 20:1 |
| The bicarbonate and carbonic acid ratio is calculated from an equation by: | Henderson-Hasselbalch |
| Acidosis and alkalosis are best defined as fluctuations in blood pH and CO2 content due to changes in: | bicarbonate buffer |
| A common cause of respiratory alkalosis is: | hyperventilation |
| Metabolic acidosis is described as a(n): | decrease in CO2 content and PCO2 with a decreased pH |
| Respiratory acidosis is described as a(n): | increase in CO2 content and PCO2 with a decreased pH |
| Normally the bicarbonate concentration is about 24 mEq/L and the carbonic acid concentration is about 1.2; pK=6.1. Using the equation pH=pK +log[salt]/[acid], calculate the pH. | 7.40 |
| The normal range for the pH of arterial blood measured at 37 degree C is: | 7.35-7.45 |
| Unless blood gas measurements are made immediately after sampling, in vitro glycolysis of the blood causes a: | fall in pH and a rise is PCO2 |
| Hydrogen ion concentration (pH) in blood is usually determined by means of what electrodes? | glass |
| In the Immunoinhibition phase of the CK-MB procedure: | M subunit is inactivated |
| The conversion of glucose or other hexoses into lactate or pyruvate is called: | glycolysis |
| The different water content of erythrocytes and plasma makes true glucose concentrations in whole blood a function of the: | hematocrit |
| In the fasting state, the arterial and capillary blood glucose concentration varies from the venous glucose concentration by approximately how many mg/dL? | 5 mg/dL higher |
| Which of the hemoglobins has glucose-6-phosphate on the amino-terminal valine of the beta chain? | A1c |
| Increased concentrations of ascorbic acid inhibit chromogen production in which glucose method? | glucose oxidase (peroxidase) |
| The function of the major lipid components of the very low density lipoproteins (VLDL) is to transport: | endogenous triglycerides |
| The most widely used support medium for electrophoretic separation of lipoproteins is: | agarose gel |
| A hospitalized patient is experiencing increased neuromuscular irritability (tetany). What test should be ordered immediately? | calcium |
| Analysis of CSF for oligoclonal bands is used to screen for what disease states? | multiple sclerosis |
| 60-75% of the plasma cholesterol is transported by: | low density lipoprotein |
| The major fraction of organic iodine in the circulation is in the form of: | thyroxine |
| Measurement of total T4 by competitive protein binding or displacement is based on the specific binding properties of: | thyroxine-binding globulin |
| Which method employs a highly specific antibody to thyroxine? | T4 by RIA |
| A mean value of 100 and a standard deviation of 1.8 mg/dL were obtained from a set of glucose measurements on a control solution. The 95% confidence interval in mg/dL would be: | 96.4-103.6 |
| The extent of what measurements agree with the true value of the quantity being measured is known as: | accuracy |
| When myocardial infarction occurs, the first enzyme to become elevated is: | CK |
| In the determination of lactate dehydrogenase at 340 nm, using pyruvate as the substrate, one actually measures the: | decrease in NADH |
| In the Jaffe reaction, creatinine reacts with: | alkaline picrate solution to yield an orange-red complex |
| What represents the end product of purine metabolism in humans? | uric acid |
| In electrophoresis of proteins, when the sample is placed in an electric field connected to a buffer of pH 8.6, all of the proteins: | have a negative charge |
| Maple syrup urine disease is characterized by an increase in which urinary amino acids? | valine, leucine, and isoleucine |
| The hemoglobin that is resistant to alkali (KOH) denaturation is: | F |
| The parent substance in the biosynthesis of androgens and estrogens is: | cholesterol |
| The biologically most active, naturally occurring androgen is: | testosterone |
| A 24-hour urine specimen (total volume=1136 mL) is submitted to the laboratory for quantitative urine protein. Calculate the amount of protein excreted per day. if the total protein is 52 mg/dL. | 591 mg |
| What is secreted by the placenta and used for the early detection of pregnancy? | human chorionic gonadotropin (HCG) |
| Decreased serum iron associated with increased TIBC is compatible with what disease state? | iron deficiency anemia |
| A characteristic of the Bence Jones protein that is used to distinguish if from other urinary proteins is its solubility: | at 100 degrees C |
| Which of the following diagrams on page 144 is an example of a peptide bond? | b |
| The principal excretory form of nitrogen is: | urea |
| A 45-year-old male of average height and weight was admitted to the hospital for renal function studies. He had the following lab results listed on page 144. Calculate the creatinine clearance for this patient in ml?min. | 100 |
| In the Malloy and Evelyn method for the determination of bilirubin, the reagent that is reacted with bilirubin to form a purple azobilirubin is: | diazotized sulfanilic acid |
| Bile acid concentrations are useful to assess: | hepatobiliary disease |
| What enzyme catalyzes the conversion of starch to glucose and maltose? | amylase (AMS) |
| A scanning of a CK isoenzyme fractionation revealed two peaks: a slow cathodic peak (CK-MM) and an intermediate peak (CK-MB). A possible interpretation for this pattern is: | myocardial infarction |
| What enzymes are used in the diagnosis of acute pancreatitis? | amylase (AMS) and lipase (LPS) |
| What is a glycolytic enzyme that catalyzes the cleavage of fructose-1, 6-diphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate? | aldolase |
| The greatest activities of serum AST and ALT are seen in: | acute hepatitis |
| an electrophoretic separation of lactate dehydrogenase isoenzymes that demonstrates an elevation in LD-1 and LD-2 in a "flipped" pattern is consistent with: | myocardial infarction |
| What is a characteristic shared by lactate dehydrogenase, malate dehydrogenase, ioscitrate dehydrogenase, and hydroxybutyrate dehydrogenase? | They catalyze oxidation-reduction reactions. |
| The protein portion of an enzyme complex is called the: | apoenzyme |
| The most heat labile fraction of alkaline phosphatase is obtained from: | bone |
| Refer ti the illustration on page 146. What id the most likely interpretation of the LD isoenzyme scan illustrated? | viral hepatitis |
| Blood specimens for digoxin assays should be obtained between 8 hours or more after drug administration because: | tissue and serum levels need to reach equilibrium |
| Bioavailability of a drug refers to the: | fraction of the drug absorbed into the systemic circulation |
| The cyclic antidepressants are classified as: | basic drugs |
| Zinc protoporphyrin of free erythrocyte protoporphyrin measurements are useful to assess blood concentrations of: | lead |
| Gas chromatography with the nitrogen/phosphorus detector is the most commonly used technique for the analysis of: | cyclic antidepressants |
| The most widley employed screening technique for drug abuse is: | Thin layer chromatography |
| Malic dehysrogenase as added to the aspartate aminotransaminase (AST) reaction to catalyze the conversion of: | oxalacetate to malate |
| Phenobarbital is a metabolite of: | primidone |
| Increased serum albumin concentrations are seen in what conditions? | dehydration |
| Which amino acid is associated with sulfhydryl group? | cysteine |
| Bereberi is associated with deficiency of: | thiamine |
| Night blindness is associated with deficiency of what vitamin? | A |
| Scurvy is associated with deficiency of what vitamins? | C |
| Pellagra is associated with deficiency of what vitamin? | niacin |
| Rickets is associated with deficiency of which vitamin? | D |
| The regulation of calcium and phosphorus metabolism is accompanied by which gland? | parathyroid |
| Lithium therapy is widely used on the treatment of: | manic-depression |
| The anticonvulsant used to control tonic-clonic (grand mal) seizures is: | phenytoin |
| A drug that relaxes the smooth muscles of the bronchial passages: | theophylline |
| A cardiac glycoside that is used in the treatment of congenital heart failure and arrhythmias by increasing the force and velocity of myocardial contraction is: | digoxin |
| A carbonate salt is used to control manic-depressive disorders is: | lithium |
| In which disease state is conjugated bilirubin a major serum component? | biliary obstruction |
| Spectrophotometers isolate a narrow band pass by means of: | prisms and grating |
| Refer to the illustration on page 151. The serum protein electrophoresis pattern shown was obtained on cellulose acetate at pH 8.6. Identify the serum protein fraction on the far right of the illustration. | albumin |
| The creatinine clearance (mL/min) is equal to: | [urinary creatinine (mg/L) x volume (mL/min)]/ plasma creatinine (mg/L) |
| A solution contains 20g of solute dissolved in 0.5 L of water. What is the percentage of this solution? | 4% |
| What is the formula for calculating the unknown concentration based on Beer's law (A=absorbance, C=concentration)? | (A unknown/A standard) x C standard |
| What id the formula for calculating absorbance given the percentage transmittance (%T) of a solution? | A = 2-log of %T |
| What if the formula for calculating the amount of moles of a chemical? | g/GMW |
| How many milliliters of a 3% solution can be made if 6g of solute are available? | 200mL |
| What is the formula for calculating the gram equivalent weight of a chemical? | MW/oxidation number |
| What is the formula for calculating the dilution of a solution (V=volume, C=concentration)? | V1 x C1 = V2 x C2 |
| What is the Henderson-Hasselbalch equation? | pH = pKa + log(salt/acid) |
| What is the formula for calculating a percent (w/v) solution? | grams of solute/volume of solvent x 100 |
| What is the formula for coefficient of variation? | (standard deviation x 100)/mean |
| Given the following values: 100, 120, 150, 140, 130 What is the mean? | 128 |
| What is the formula for arithmetic mean? | sum of values/number of values |
| What of the formula for calculating the molarity of a solution? | number of moles of solute/L of solution |
| The results on page 154 were obtained. Given the data, calculate the patient;s creatinine clearance in mL/min. | 104 |
| 25g of NaOH (MW=40) is added to0.5L of water. What is the molarity of this solution if an additional 0.25L of water is added to this solution? | 0.83 M |
| 4 mL of water is added to 1 mL of serum. This represents what serum dilution? | 1:5 |
| 80 g of NaOH (MW=40) is how many gram-equivalents? | 2 |
| How many grams of H2SO4 (MW=98) are in 750 mL of 3 N H2SO4? | 110 |
| What is the normality of a solution that contains 280 g of NaOH (MW= 40) in 2000 mL of solution? | 3.5 N |
| A serum potassium is 19.5 mg/100 mL. This value is equal to how many mEq/L (MW of K=39)? | 5.0 |
| how many milliliters of 0.25 N NaOH are needed to make 100 mL of a 0.05 N solution of NaOH? | 20 mL |
| An arterial blood specimen submitted for blood gas analysis was obtained at 8:30 AM but was not received in the laboratory until 11:00 AM. The technologist should: | request a new arterial specimen be obtained |
| A potassium level of 6.8 m/Eq/L is obtained. Before reporting the results, the first step the technologist should take is to: | check the serum for hemolysis |
| Specimens for blood gas determination should be drawn into a syringe containing: | heparin |
| A patient has the test results listed on page 156. This patient most likely has: | hyperparathyroidism |
| If the total bilirubin is 4.3 mg/dL and the conjugated bilirubin is 2.1 mg/dL, the unconjugated bilirubin is: | 2.2 mg/dL |
| The measurement of light scattered by particles in the sample is the principle of: | nephelometry |
| The measurement of the amount of electricity passing between two electrodes in an electrochemical cell is the principle of: | coulometry |
| Coulometry is used to measure: | chloride |
| What lipid results would be expected to be falsely elevated on a serum specimen from a non- fasting patient? | triglyceride |
| Turbidity in serum suggests elevation of: | chylomicrons |
| What would be an example of glucose-specific colorimetric method? | glucose oxidase |
| The relative migration rate of proteins on cellulose acetate is based on: | ionic charge |
| As part of a hyperlipidemia screening program, the results listed on page 157 were obtained on a 25-year-old woman 6 hours after eating. What is the best interpretation of these results? | The cholesterol is normal but the triglycerides are elevated, which may be attributed to the recent meal. |
| Enzyme-multiplied immunoassay techniques (EMIT) differ from all other types of enzyme immunoassays in that: | no separation of bound and free antigen is required |
| Refer to the graph on page 158. A new methodology for amylase has been developed and compared with the existing method as illustrated in the graph. the new method can be described as: | good correlation with consistent bias |
| a 48-year-old woman with mild jaundice has the serum results listed on page 158. What sources most contributes to the patient's serum alkaline phosphatase activity? | liver |
| A potentiometric electrode that measures an analyte that passes through a selectively permeable membrane and rapidly enters into an equilibrium with an electrolyte solution is: | PCO2 |
| Ion selective electrodes are called selective rather than specific because they actually measure the: | activity of one ion much more than other ions present |
| An automated method for measuring chloride that generates silver ions in the reaction is: | coulometry |
| A patient's values are as listed on page 159. What is the patient's free thyroxine index? | 1.6 |
| A person suspected of having metabolic alkalosis would have what laboratory findings? | CO2 content and pH elevated |
| refer to the graph on page 160. The HCG levels shown in the above graph most probably represent: | normal pregnancy |
| Fluctuation of the needle on a coulometric type titrator is most probably due to: | dirty electrodes |
| Iodine 125 has a physical half-life of 60.0 days. A sample tested today had activity of 10,000 CMP/mL. How many days from today will the count be 1250 CMP/mL? | 180 |
| What is most likely to be ordered in addition to serum calcium to determine the cause of tetany? | magnesium |
| A 9-month-old boy from Israel has gradually lost the ability to sit up & developes seizures. he has an increased amount of a phospholipid called GM2-ganglioside in his neurons, & he lacks the enzyme hexosaminidase A in his leukocytes. The findings suggest | Tay-Sachs disease |
| An adult diabetic with renal complications has the results listed on page 161. On the basis of these results, the calculated serum osmolality is: | 304 mOsm/kg |
| the formation of estriol in a pregnant woman is dependent on: | fetal and placental function |
| Arterial blood collected in a heparinized syringe but exposed to room air would cause what changes in the specimen? | elevated PO2, decreased PCO2, and elevated pH |
| Magnesium carbonate is added in an iron binding capacity determination in order to: | remove excess unbound iron |
| An elevated serum iron with normal iron binding capacity is most likely associated with: | pernicious anemia |
| A patient's blood was drawn at 8am for a serum iron determination. The result was 85 ug/dL. a repeat specimen was drawn at 8pm; the serum was stored at 4 degrees C & run the next morning. The result was 40ug/dL. these results are most likely due to: | the time of day the second specimen was drawn |
| A patient with glomerulonephritis would present what serum results? | BUN increased |
| Absorption of vitamin B12 requires the presence of: | intrinsic factor |
| Refer to the illustration on page 163. The above symbol posted in an area would indicate what hazard? | flammable |
| A 68-year-old man arrives in the ER with a glucose level of 722 mg/dL, and serum acetone of 4+ undiluted. An arterial blood gas from this patient is likely to indicate: | low pH |
| what battery of tests is most useful in evaluating an anion gap of 22mEq/L? | BUN, creatinine, salicylate, and methanol |
| Serum levels that define hypoglycemia in preterm or low birth weight infants are: | lower than in adults |
| Oligoclonal bands are present on electrophoresis of concentrated CSF and also concurrently tested serum of the same patient. the porper interpretation is: | non diagnostic for multiple sclerosis |
| In developing the reference foe a new EIA for CEA, the range for the normal population was broader than that published by the vendor. Controls are acceptable with a narrow coefficient of variation. This may be explained by: | inclusion os nonsmokers and smokers in the study population |
| Most automated blood gas analyzers directly measure: | pH, PCo2, and PO2 |
| In the assay of lactate dehydrogenase (LD), the reaction is dependent on which of the following co- enzyme systems? | NAD/NADH |
| Creatinine clearance is used to estimate the: | glomerular filtration rate |
| A pH of 7.0 represents a H+ concentration of: | 100 nmol/L |
| The chemical composition of HDL-cholesterol corresponds to: | 5% Triglyceride, 15% Cholesterol, 50% Protein |
| The principle of the tablet test for bilirubin in urine or feces is: | chemical coupling of bilirubin with a diazonium salt to form a purple color |
| To make up 1 L of 1.000 N NaOH from a 1.025 N NaOH solution, how many milliliters of the NaOH should be used? | 975.6 |
| If 0.5 mL of a 1:300 dilution contains 1 antigenic unit, 2 antigenic units would be contained in 0.5 mL of a dilution of: | 1:150 |
| If the pKa is 6.1, the CO2 content is 25 mmol/L, the salt equals the total CO2 content minus the carbonic acid, the carbonic acid equals 0.03 x PCO2, and PCO2 is 40 mm Hg, it may be cancluded that: | pH=6.1+log[(25-1.2)/(1.2)] |
| Blood was collected in a serum separator tube from a patient who had been fasting since midnight. The time of collection was 7:00 AM. The laboratory test that should be re-collected is: | triglycerides |
| the cellulose acetate electrophoresis at pH 8.6 of serum proteins will show an order of migration beginning with the fastest migration as follows: | albumin, alpha-1 globulin, alpha-2 globulin, beta globulin, gamma globulin |
| The TRH (thyrotropin-releasing hormone) stimulation test is useful in assessing what? | depression |
| A patient has the results listed on page 243. The best conclusion ids that this patient has: | iron hemachromatosis |
| What elevates carboxyhemoglobin? | exposure to carbon monoxide |
| A patient is admitted to the emergency room in a state of metabolic alkalosis. What would be consistent with this diagnosis? | high TCO2, increased HCO3 |
| For the past 3 weeks serum estriol levels in a pregnant woman have been steadily increasing. This is consistent with: | a normal pregnancy |
| In the atomic absorption method for calcium, lanthanum is used: | to prevent phosphate interference |
| A patient has the thyroid profile listed on page 167. This patient most probably: | has increased protein-bound T4 |
| The following data were calculated on a series of 30 determinations of serum uric acid control: mean=5.8mg/dL, 1 Standard Deviation=0.15mg/dL. If confidence limits are set at +/- 2 standard deviations, what represents the allowable limits for the control? | 5.50-6.10 mg/dL |
| The reason carbon monoxide is so toxic is because it: | has 200 times the affinity of oxygen for hemoglobin binding sites |
| Clinical assays for tumor markers are most important for: | monitoring the course of a known cancer |
| Estrogen and progesterone receptor assays are useful in assessing prognosis in what? | breast cancer |
| A chemiluminescent EIA: | is quantitative by the amount of light produced by the reaction |
| The selectivity of an ion-selective electrode is determined by the: | properties of the membrane used |
| Valinomycin enhances the selectivity of the electrode used to quantitate: | potassium |
| A 45-year-old woman has a fasting serum glucose concentration of 95 mg/dL and a 2-hour postprandial glucose concentration of 105 mg/dL. The statement that best describes this patient's fasting serum glucose concentration is: | normal, reflecting glycogen breakdown by the liver |
| An HPLC operator notes that the column pressure is too high, is rising too rapidly, and the recorder output is not producing normal peaks. The most probable cause of the problem is: | effluent line obstructed |
| An infant with diarrhea is being evaluated for a carbohydrate intolerance. His stool yields a positive copper reduction test and a pH of 5.0. It should be concluded that: | further tests are indicated |
| In a centrifugal analyzer, centrifugal force is used to: | transfer liquids from the inner disc to the outer cuvette |
| A fasting serum sample from an asymptomatic 43-year-old woman is examined visually and chemically with the results listed on page 169. This sample contains predominantly: | chylomicrons and very-low-density lipoproteins (VLDL) |
| Factor that contribute to a PCO2 electrode's requiring 60-100 seconds to reach equilibrium include the: | diffusion characteristics of the membrane |
| In which of the following conditions would a NORMAL level of creatine kinase be found? acute myocardial infarct, hepatitis, progressive muscular dystrophy, intramuscular injection | hepatitis |
| The direction in which albumin migrates (ie. toward anode or cathode) during electrophoretic separation os serum proteins, at pH 8.6, is determined by: | the ionization of the carboxyl groups, yielding a net negative charge |
| In a double-beam photometer, the additional beam is used to: | correct for variations in light source intensity |
| Gel filtration chromatography is used to separate: | compounds on the basis of molecular weight and size |
| Aminotransferase enzymes catalyze the: | exchange of amino and keto groups between alpha-amino and alpha-keto acids |
| Ninety percent of the copper present in plasma is bound to: | ceruloplasmin |
| In lipoprotein phenotyping. chylomicrons are present in the plasma of persons with what lipoprotein phenotypes? | I and V |
| A 600 mg/dL glucose solution is diluted 1:30. The concentration of the final solution in mg/dL is: | 20 |
| Monitoring long-term glucose control in patients with adult onset diabetes mellitus can best be accomplished by measuring: | hemoglobin A1c |
| The disease most often associated with elevations of lactate dehydrogenase isoenzymes 4 and 5 on electrophoresis is: | liver disease |
| The following five sodium control values (mEq/L) were abtained: 140, 135, 138, 140, 142 Calculate the coefficient of variation. | 1.9% |
| A spectrophotometer is being considered for purchase by a small laboratory. what specifications reflects the spectral purity of the instrument? | band width |
| An LD1 greater than LD2 fraction of lactic dehydrogenase is most often associated with: | myocardial infarction |
| How many milliliters of 30% bovine albumin are needed to make 6 mL of a 10% albumin solution? | 2 |
| What substrate provide the best specificity for prostatic acid phosphatase? | thymolphthalein monophosphate |
| A lipemic serum is separated and frozen at -20 degrees C for assay at a later date. One week later, prior to preforming an assay for triglycerides, the specimen should be: | warmed to 37 degree C and mixed thoroughly |
| In the proper use of cobalt treated anhydrous CaCl2, the desiccant should be: | changes when it turns pink |
| A serum sample was assayed for bilirubin at 10 AM and the result was 12 mg/dL. The same sample was retested at 3PM. The result mow is 8 mg/dL. The most likely explanation for this discrepancy is: | the sample was exposed to light |
| To prepare a physiologic saline solution, dissolve: | 8.5 g NaCl in 1 L H2O |
| A chemistry assay utilizes a bichromatic analysis. This means that absorbance readings are taken at: | two wavelengths to correct for spectral interference from another compound |
| Serial bilirubin determinations are charted on page with the best explanation for the results due to: | sample exposure to light |
| Infamilial hypercholesterolemia, tha hallmark finding is an elevation of: | low-density lipoproteins |
| Pregnant women with symptoms os thirst, frequent urination, or unexplained weight loss should have what test preformed? | glucose tolerance test |
| The most consistent analytical error involves in the routine determination of HDL-cholesterol is caused by: | a small concentration of APO-B containing lipoproteins after precipitation |
| Nephelometers measure light: | scattered at the right angle to the light path |
| What substance gives feces its normal color? | urobilin |
| Premature atherosclerosis can occur when what becomes elevated? | low density lipoproteins |
| If the LDL-cholesterol is to be calculated by the Friedenwald formula, what are the two measurements that need to be carried out by the same chemical procedure? | total cholesterol and HDL-cholesterol |
| High levels of what lipoprotein class are associated with decreased risk of accelerated atherosclerosis? | HDL |
| Following overnight fasting, hypoglycemia in adults is defined as a glucose of: | <=45 mg/dL |
| The first step in the quantitation of serum iron is: | separation of iron from transferrin |
| The principle of the occult blood test depends on the: | peroxidase-like activity of hemoglobin |
| In an internal standard flame photometer, the internal standard is used to: | correct for variations in flame and atomizer characteristics |
| Which of the following wavelengths is within the ultraviolet range? | 340 nm |
| A glucose determination was read on a spectrophotometer. The absorbance reading of the standard was 0.30. The absorbance reading of the unknown was 0.20. The value of the unknown is: | two thirds of the standard |
| Aspartate aminotransterase (AST) is characteristically elevated in diseases of the : | liver |
| The enzyme that exists chiefly in skeletal muscle, heart, and brain; is grossly elevated in active muscular dystrophy; and rises early in myocardial infarction is: | creatine kinase |
| The primary function of serum albuminin the peripheral blood is to: | maintain colloidal osmotic pressure |
| Most chemical methods for determining total protein utilize what reactions? | biuret |
| The mean value of a series of hemoglobin controls was found to be 15.2 g.mL, and the standard deviation was calculated at 0.20. Acceptable control range for the laboratory is +/- 2 standard deviations. What represents the allowable limits for the control? | 14.8-15.6 g/dL |
| The presence of a C-reactive protein in the blood is an indication of: | an inflammatory process |
| Chromatography is based on the principle of: | differential solubility |
| The T3-uptake test is based on: | relative binding of T3 and T4 to globulin |
| The most specific method for the assay of glucose utilizes: | hexokinase |
| The enzyme present in almost all tissues that may be separated by electrophoresis into five components is: | lactate dehydrogenase |
| In quality control, +/- s standard deviations for the mean what percent of the sample population? | 95 % |
| The term used to describe reproducibility is: | precision |
| When 0.25 mL is diluted to 20 mL, the resulting dilution is: | 1:80 |
| The extent to which measurements agree with or approach the true value of the quantity being measured is referred to as: | accuracy |
| A breakdown product of hemoglobin is: | bilirubin |
| When exact concentration of the solute of a solution is known and is used to evaluate the concentration of an unknown solution, the known solution is: | standard |
| A serum glucose was too high to read, so a 1:5 dilution using saline (A) was made. Dilution A was tested & was again too high to read. A further 1:2 dilution was made using saline (B). To calculate the result, the dilution B value must be multiplied by: | 10 |
| In performing a spinal fluid protein determination, the specimen is diluted 1 part spinal fluid to 3 parts saline to obtain a result low enough to measure. To calculate the protein concentration the results must be: | multiplied by 4 |
| In order to prepare 100 mL of 15 mg/dL BUN working standard from a stock standard containing 500 mg/dL of urea nitrogen, the amount of stock solution used is: | 3 mL |
| In monitoring glomerular function, what test has the highest sensitivity? | creatinine clearance |
| An automated CK assay gives a reading that is above the limits of linearity. A dilution of the serum sample is made by adding 1 mL of serum to 9 mL of water. The instrument now reads 350 U/L. The correct report on the undiluted serum should be: | 3500 U/L |
| Blood received on the laboratory for blood gas analysis must meet what requirements? | on ice, no clots, no air bubbles |
| An electrode has a silver/silver chloride anode & a platinum wire cathode. It is suspended in KCl solution & separated from the blood to be analysed by a selectively permeable membrane. Such an electrode is used to measure what? | PO2 |
| Which blood gas electrode is composed of calomel and glas? | CO2 |
| A thick white turbid specimen was received in the lab labeled as pericardial fluid. A microscopic examination was performed, and the differential included 90% PMN's. The fluid is: | purulent |
| In the assay of lactate dehydrogenase, what product is actually measured? | NADH |
| The sodium content (in grams) in 100 g of NaCl ( atomic weights: Na=23.0, Cl=35.5) is approximately: | 40 |
| Bromcresol purple at a pH of 5.2 is used in a colorimetric method to measure: | albumin |
| In spectrophotometry, the devise that allows for a narrow band of wavelengths is the: | monochromator |
| The following results were obtained from a set of automated white blood cell counts performed on 40 samples: Standard deviation 153.2/uL, Mean value 12,450/uL. Calculate the coefficient of variation: | 1.2% |
| If a fasting glucose were 90 mg/dL, which of the following 2-hour postprandial glucose results would most closely represent normal glucose metabolism? 55, 100, 180, or 260 mg/dL | 100 mg/dL |
| The bilirubin results on page 181 are obtained on a patient. Given that the controls were within range each day, what is a probable explanation for the results on day 4? | specimen had a prolonged exposure to light |
| In flame emission photometry, an excited arbital electron returns to ground state and emits: | a photon of light with specific wavelength for the element being measured |
| The first procedure to be followed if the blood gas instrument is out of control for all parameters is: | recalibrate, then repeat control |
| What method for quantitation of high-density lipoprotein is most suited for clinical lab use? | precipitation |
| Urobilinogen is formed in the: | intestines |
| A healthy person with a blood glucose of 80 mg/dL would have a simultaneously determined cerebrospinal fluid glucose value of: | 50 |
| Upon completion of a run of cholesterol tests, the technician recognizes that the controls are not within the 2 standard deviations confidence range. What is the appropriate course of action? | run a new set of controls and repeat specimens |
| A technician is asked by the supervisor to prepare a standard solution solution from the stock standard. What is the glassware of choice for this solution. | volumetric flask |
| Slight hemolysis can cause erroneous laboratory results in which serum analyte? | K+ |
| The volume of 25% stock sulfosalicylic acid needed to prepare 100 mL of 5% working solution is: | 20 mL |
| A stool specimen that appears black and tarry should be tested toe the presence of: | occult blood |
| In bilirubin determinations, the purpose of adding a concentrated caffeine solution or methyl alcohol is to: | allow indirect bilirubin to react with color reagent |
| To prepare 25 mL of 3% acetic acid, how much glacial acid is needed? | 0.75 mL |
| How many grams of sodium chloride are needed to prepare 1 L of 0.9% normal saline? | 9.0 |
| The first step in analyzing a 24-hour urine specimen for quantitative urine protein is: | measure the total volume |
| How many milliliters of reagent are needed to prepare 5 mL of a 1:25 dilution? | 0.2 |
| What is the first step in preparing a spectrophotometer for an assay? | adjust wavelength selector |
| A 25-year-old man became nauseated and vomited 90 minutes after receiving a standard 75-g charbohydrate dose for an oral glucose tolerance test. The best course of action is: | draw blood for glucose and discontinue test |
| A common cause of falsely increased LD1 fraction of lactic dehydrogenase is: | specimen hemolysis |
| The presence of which of the following isoenzymes indicates acute myocardial damage? CK-MM, CK-MB, CK-BB or none of the above | CK-MB |
| Cerebrospinal fluid for glucose assay should be: | analyzed immediately |
| The preparation of a patient for standard glucose tolerance testing should include: | high carbohydrate diet for 3 days |
| Measurement of the serum acid phosphatase is used to detect neoplastic disease of the: | prostate |
| A serum sample demonstrates an elevated result when tested with the Jaffe reaction. This indicates: | renal functional impairment |
| An increase in serum acetone is indicative of a defect in the metabolism of: | carbohydrates |
| To prepare 40 mL of a 3% working solution, a technician would use what volume of stock solution? | 1.2 mL |
| A technician is preparing a 75% solution. What volume of stock solution should be used to prepare 8 mL? | 6.0 mL |
| The results on page 186 are from a 21-year-old patient with a back injury who appears otherwise healthy. The best interpretation of these results is that: | all values are consistent with a normal healthy individual |
| The nanometer is a measurement of: | wavelength of radiant energy |
| If the total bilirubin is 3.1 mg/dL and the conjugated bilirubin is 2.0 mg.dl, the unconjugated bilirubin is: | 1.1 mg/dL |
| The ability of a procedure to measure only the component(s) it claims to measure is called: | specificity |
| The most widely used methods for bilirubin measurement are those based on the: | Jendrassik Grof method |
| After a difficult venipuncture requiring prolonged application of the tourniquet, the serum K+ was found to be 6.8 mEq/L. The best course of action is to: | repeat the test using freshly drawn serum |
| A serum sample for acid phosphatase determination is best prepared for room temperature storage by: | adding an acid stabilizer |
| Serum from a patient with metastatic carcinoma of the prostate was separated from the clot and stored at room temperature. The results on page 187 were obtained. The technician should repeat the: | acid phosphatase with freshly drawn serum |
| When performing a manual protein analysis on a xanthochromic spinal fluid, the technician should: | make a patient blank |
| Which of the following 2-hour postprandial glucose values demonstrates unequivocal hyperglycemia diagnostic for diabetes mellitus? 160, 170, 180, or 200 mg/dL | 200 mg/dL |
| the glycosylated hemoglobin value represents a time average of glucose concentration during the preceding: | 8-12 weeks |
| Te ensure an accurate ammonia level result, the specimen should be: | spun,separated, iced, and tested immediately |
| The most specific enzyme test for acute pancreatitis is: | lipase |
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