Laboratory

Blood Collection and Testing Basics

• Needle size is indicated by gauge numbers; larger numbers represent smaller needle diameters.
• Cellular elements in blood essential for coagulation include platelets and clotting factors.
• Blood type O negative is known as the universal donor as it can be given to any patient.
• To prevent scratches, lenses of microscopes should be cleaned with lens paper.
• Phlebotomy needles should be stored in a clean, dry area to maintain sterility.
• Venipuncture at certain sites, like the back of the hand, can yield reliable results, while other sites may introduce variability.

Blood Collection Equipment and Techniques

• A blood collection vacuum tube is critical for drawing blood from veins.
• Capillary action allows liquid to move into a tube or pipette through adhesion and cohesion.
• Lumbar puncture is the method used for detecting Meningitis.
• Absorption and utilization of a substance are measured through specific absorption tests.
• Compatibility testing, known as crossmatching, is performed before blood transfusions.
• Venipuncture usually does not require skin puncture for tests like blood cultures.
• Arterial blood gas (ABG) samples typically require 1-3 mL of blood.

Procedures and Precautions

• Complications from arterial blood gas collection include hematoma, arterial injury, and infection.
• If a hematoma forms during phlebotomy, apply pressure, and elevate the site to minimize bleeding.
• A special winged infusion set, known as a butterfly needle, can remain in a vein for 48 hours for medication delivery.
• The Activated Clotting Time (ACT) test monitors anticoagulation during procedures.
• Ethanol tests cannot be prepped with alcohol due to contamination risk; use sterile saline instead.
• The bevel of the needle must face upward before entering a vein for optimal access.

Types of Specimens and Testing Considerations

• A retractable needle sheath is designed for safety after use, preventing needle-stick injuries.
• Items not considered as skin puncture equipment include large bore needles.
• Needles are color-coded according to gauge size, allowing for quick identification.
• The most common antiseptic for blood draws is 70% isopropyl alcohol.
• Hemoguard refers to a type of blood collection tube with a protective barrier.

Blood Components and Analysis

• Blood is composed of formed elements (cells) suspended in plasma.
• An anticoagulated blood specimen is obtained through venipuncture without clotting.
• Labeled specimens must include patient identification, date, time, and collector's initials.
• Reasons to reject a specimen include hemolysis or improper labeling.
• Blood separates into plasma and formed elements when allowed to stand undisturbed.

Venipuncture and Specimen Collection Techniques

• The median cubital vein is the most commonly used for venipunctures.
• Warming the site before venipuncture promotes better blood flow and easier access.
• Hematomas during venipuncture often result from penetrating a vein too deeply.
• Controlling the lancet depth during skin puncture is crucial to prevent nerve damage.
• Blood smears for cellular evaluation should be thin and even.

Specific Tests and Functions

• Blood culture specimens require sterile containers and proper site cleaning.
• The epinephrine tolerance test assesses the body's response to epinephrine.
• There are five major types of proteins in blood, including albumin and globulins.
• Collecting specimens too early or too late can lead to unreliable lab results.
• Spinal fluid cultures help diagnose infections of the central nervous system.

Liver and Insulin Function Tests

• Dyes like bilirubin are used in liver function tests to assess hepatic health.
• Insulin release tests evaluate the pancreas's ability to produce insulin.
• Anticoagulants hinder coagulation, preventing blood from clotting.
• Capillaries are small vessels that facilitate gas and nutrient exchange; they are not true about being under pressure or prone to vice versa.

Endocrine and Other Investigations

• Cholesterol testing evaluates lipid levels and cardiovascular health.
• To assess endocrine function, specific hormone tests are performed.
• Failed venipuncture can occur due to vein collapse or improper needle angle.
• A puncture-resistant container is essential for disposing of sharps safely.
• Gout diagnosis often relies on uric acid level tests in the blood.

Heart Disease and Blood Characteristics

• Coronary artery disease and atherosclerosis are identified through lipid panels and stress tests.
• Lancets are designed for precise skin punctures with minimal discomfort.
• Capillary punctures often use microcollection devices for small blood samples.
• Characteristics of the capillary puncture technique include requiring less blood and reducing invasiveness.

Patient Considerations and Safety

• Optimal venipuncture sites include the antecubital fossa and forearm.
• Special care is crucial when drawing blood from elderly patients due to fragile veins.
• Alternative skin prep solutions should be used if alcohol is contraindicated.
• Clotting process is known as coagulation, essential for hemostasis.
• Plasma is the clear, yellow fluid that carries blood cells and proteins.

Clinical Laboratory Testing

• A reference point for lab tests serves as a standard for comparison (reference range).
• Prolonged bleeding time may signal clotting disorders or platelet dysfunction.
• The most common laboratory-acquired infection arises from handling blood specimens.
• WBC represents the white blood cell count, an essential lab test for infections.
• Hemoconcentration might be caused by dehydration or prolonged tourniquet application.
• Factors such as intense exercise or stress can alter basal state test results.