Phlebotomy (CH9)
What is the most common type of error in the preanalytical phase of blood collection?
Patient identification error.
What is the primary function of platelets in hemostasis?
To form a platelet plug and aid in coagulation.
What is the functional unit of the kidney and its three main processes?
Nephron; filtration, reabsorption, and secretion.
Which hormone lowers blood glucose and how does it work?
Insulin; promotes cellular uptake and storage as glycogen or fat.
What is a karyotype?
An arrangement of chromosomes by size and centromere position.
Define antigen and antibody.
Antigen: A substance that triggers antibody production; Antibody: A protein produced in response to an antigen.
List two main reasons for blood transfusion.
Restore oxygen-carrying capacity and maintain blood volume.
Name three components of the chain of infection.
Reservoir, means of transmission, susceptible host.
What is the correct sequence of events when platelets are activated during hemostasis?
Adhesion → Shape change → Release of granules → Aggregation → Formation of platelet plug.
What hormone controls water reabsorption in the collecting tubules?
Antidiuretic hormone (ADH).
What is the primary extracellular cation and its main function?
Sodium (Na⁺); regulates water balance and osmotic pressure.
What are the base-pairing rules for RNA?
Adenine pairs with uracil; cytosine pairs with guanine.
Which antibody appears first in a primary immune response?
IgM.
What is the purpose of irradiated blood products?
To prevent graft-versus-host disease (GVHD).
Which anticoagulant is preferred for hematology tests, and what does it do?
EDTA (Ethylenediaminetetraacetic acid). It works by chelating (binding) ionized calcium (Ca²⁺) in the blood.
What are coagulation factors?
Coagulation factors are plasma proteins that circulate in an inactive form and become activated during the clotting process.
What is the normal range for urine specific gravity?
1.003 to 1.035.
What is the normal urea nitrogen/creatinine ratio and what does a high ratio indicate?
12–20; high ratio may indicate postrenal obstruction or renal disease.
Name the three types of RNA and state their primary functions.
mRNA: Carries DNA instructions to make proteins.
tRNA: Delivers amino acids for protein building.
rRNA: Forms the site for protein synthesis.
Name the three complement activation pathways.
Classical, alternative, lectin.
Name two coagulation factors found in cryoprecipitate.
Fibrinogen and Factor VIII.
Give one example of a light-sensitive analyte and how it should be handled.
Bilirubin; wrap the tube in aluminum foil immediately after collection or use a light-protected protected tube
Which pathway is triggered by tissue thromboplastin?
Extrinsic pathway.
Define polyuria and give its threshold in 24 hours.
Excretion of >2000 mL urine in 24 hours.
Which lipoprotein is considered “good cholesterol” and what is its role?
HDL; removes excess cholesterol and transports it back to the liver.
What is an epigenetic change?
A modification that affects gene expression without altering DNA sequence.
Differentiate between active and passive immunity.
Active: Body produces its own antibodies; Passive: Antibodies are received from another source.
Which antibody class is naturally occurring in the ABO system?
IgM (anti-A and anti-B).
How does high altitude affect the draw volume in evacuated tubes?
It decreases draw volume due to lower ambient pressure.
Name two natural anticoagulant proteins in the body.
Protein C and Protein S.
What is the main function of the ascending tubule of the Loop of Henle?
It actively reabsorbs sodium and chloride but is impermeable to water, helping dilute the urine.
Name two enzymes commonly measured to assess liver function.
ALT and AST.
What does FISH stand for and what is its purpose?
Fluorescence In Situ Hybridization; visualizes genes or chromosomes in cells.
What is the function of T lymphocytes versus B lymphocytes?
T cells: Cell-mediated immunity; B cells: Produce antibodies (humoral immunity).
What does the D antigen determine in the Rh system?
The presence of the D antigen means the person is Rh positive; absence means Rh negative. This antigen is highly immunogenic and critical for transfusion compatibility.