Blood: Most Common Body Fluid Specimen Analyze in Clinical Laboratory

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The body fluid most commonly analyzed in the clinical laboratory is blood. Whole blood can be allowed to clot in a clean plastic collection tube and then be centrifuged and the serum removed for testing in clinical chemistry. Conversely, clotting can be prevented by allowing the whole blood to mix with an anticoagulant such as lithium heparin so that it can be measured as whole blood or centrifuged to obtain the plasma for analysis. Other types of testing performed in the clinical laboratory, such as the complete blood count, require anticoagulated, well-mixed whole blood.

Basic Phlebotomy or Venipuncture - Blood Collection Guide

How To Collect Venous Blood

Healthcare facilities provide a comprehensive training for collection of blood specimen. Here are the basic steps that are necessary guide to collect a blood sample.

1. Observe standard precautions . If latex allergy is suspected, use latex-free supplies and equipment.
2. Position and tighten a tourniquet on the upper arm to produce venous congestion.
3. Ask the patient to close the fist in the designated arm. Select an accessible vein.
4. Cleanse the puncture site and dry it properly with sterile gauze. Povidone-iodine must dry thoroughly.
5. Puncture the vein according to accepted technique. Usually, for an adult, anything smaller than a 21-gauge needle might make blood withdrawal more difficult. A Vacutainer system syringe or butterfly system may be used.
6. Once the vein has been entered by the collecting needle, blood will fill the attached vacuum tubes automatically because of negative pressure within the collection tube.
7. Remove the tourniquet before removing the needle from the puncture site or bruising will occur.
8. Remove needle. Apply pressure and sterile dressing strip to site.

Study Guide- Phelobotomy Examination

This is  a study guide in phlebotomy. The proper use use of blood collection tubes and the order of draw during blood collection.

Venipuncture- Definition and Purposes

Venipuncture allows procurement of larger quantities of blood for testing. Usually, the antecubital veins are the veins of choice because of ease of access. Blood values remain constant no matter which venipuncture site is selected, so long as it is venous and not arterial blood. This procedure is performed by medical laboratory scientists, medical practitioners, some EMTs,paramedics, phlebotomists, dialysis technicians, and other nursing staff. Venipuncture is one of the most routinely performed invasive procedures and is carried out for any of five reasons: 

1. to obtain blood for diagnostic purposes
2. to monitor levels of blood components
3. to administer therapeutic treatments including medications, nutrition, or chemotherapy
4. to remove blood due to excess levels of iron or erythrocytes (red blood cells);
5. to collect blood for later uses, mainly transfusion either in the donor or in another person.

Capillary Puncture (Skin Puncture or Prick Method) Procedure

This method is preferably used in peripheral blood smear preparation but applicable also in other hematologic examinations.

Different Blood Collection Tubes and Uses

When you are a phlebotomist, the very basic thing to consider is to familiarized yourself to the different collection tubes used in the laboratory and their corresponding uses.

Basic Methodology of Laboratory Testing

• Follow testing procedures accurately. Verify orders and document them with complete, accurate, and legible information. 
• Document all drugs the patient is taking because these can be a factor that can influence test outcomes.

Factors that Alter Laboratory Results

If you're collecting a sample for a patient for laboratory testing, make sure to consider some factors that may possibly alter his/her results. Depending on the procedure requested, these factors may include:

Common Factors of Specimen Rejection in the Laboratory

If proper collection of samples is not correctly done in a clinical specimen, this may lead to inaccurate results.Below is a list of possible factors for specimen rejection:

Point-of- Care Testing (POCT)- Definition and Application

Point-of-Care Testing refers to tests done in the primary care setting. In acute care settings (eg, critical care units, ambulances), state-of-the-art testing can produce rapid reporting of test results. 

Testing in the home care environment requires skill in procedures such as drawing blood samples, collecting samples from retention catheters, proper specimen labeling, documentation, specimen handling, and specimen transporting. Moreover, teaching the patient and his or her significant others how to collect specimens is an important part of the process.

The Standard Precautions in the Laboratory

Standard precautions is the combination of the major features of the Universal Precautions(UP) and Body Substance Isolation(BSI).It should be used for the care of patients and also for the protection of the healthcare workers. Standard precautions include the following:

Personal Protective Equipment (PPE)

Personal Protective Equipment(PPE)

Personal protective equipment encountered by laboratorians includes gloves, gowns or laboratory coats, masks, goggles, face shields, and Plexiglas countertop shields. Gloves are worn to protect the health-care worker’s hands from contamination by patient body substances and to protect the patient from possible microorganisms on the health-care worker’s hands. Wearing gloves is not a substitute for handwashing. Hands must always be washed when gloves are removed. A variety of gloves are available, including sterile and non-sterile, powdered and unpowdered, and latex and non-latex.

The Body Substance Isolation (BSI)

Body substance isolation (BSI) is a  modification of universal precautions and is not limited to bloodborne pathogens and considers all body fluids and moist body substances to be potentially infectious. Personnel should wear gloves at all times when encountering moist body substances. Unlike UP(Universal precautions) , a disadvantage of the BSI guideline is that it does not recommend handwashing after removing gloves unless visual contamination is present. The practice of BSI was common in Pre-Hospital care and Emergency Medical Services due to the often unknown nature of the patient and his/her disease or medical conditions. It was a part of the National Standards Curriculum for Prehospital Providers and Firefighters. The features of UP and BSI have now been combined and are called “Standard Precautions”.

The Universal Precuations (UP)

Universal precautions (UP) were instituted by the CDC in 1985 to protect health-care workers from exposure to bloodborne pathogens, primarily hepatitis B virus (HBV) and HIV. Under universal precautions, all patients are assumed to be possible carriers of bloodborne pathogens. Transmission may occur by skin puncture from a contaminated sharp object or by passive contact through open skin lesions or mucous membranes. The guideline recommends wearing gloves when collecting or handling blood and body fluids contaminated with blood, wearing face shields when there is danger of blood splashing on mucous membranes, and disposing of all needles and sharp objects in puncture-resistant containers without recapping.

Material Collection from Suspected Herpetic Lesions

Principle:

Herpesvirus is best recovered from the base of active lesions in the vesicular stage. The older the lesion, the less likely it will yield viable virus.

Method:

1. Open the vesicles with a small gauge needle or Dacron- tipped swab.
2. Rub the base of the lesion vigorously with a small cotton-tipped or Dacron-tipped swab to recover infected cells.
3. Place the swab into viral transport medium and refrigerate until inoculated to culture media. Specimens in media may be stored at -70⁰C for extended periods without loss of viral yield.
4. If large vesicles are present, material for culture may be aspirated directly by needle and syringe.
5. Material from another lesion can be applied directly to a glass slide for a Tzanck preparation (cytology) with Wright- Giemsa stain for detection of multinucleated giant cells, or for fluorescent antibody stain for detection of viral antigens.