NCCT National Certified Phlebotomy Technician General 2 — Questions and Answers
Question 1: What is the main function of the lymphatic system in relation to blood circulation?
- To produce red blood cells
- To return excess interstitial fluid to the bloodstream and support immune function (Correct answer)
- To transport oxygen to tissues
- To regulate blood pressure
Correct answer: To return excess interstitial fluid to the bloodstream and support immune function
The lymphatic system collects excess fluid that leaks from capillaries into tissues and returns it to the venous system, while also filtering pathogens through lymph nodes.
The lymphatic system is a network of vessels, nodes, and organs that serves two primary functions: fluid balance and immune defense. Lymphatic capillaries collect excess interstitial fluid and return it to the venous system via the thoracic duct and right lymphatic duct.
Question 2: Which organ is primarily responsible for producing most of the body's clotting factors?
- Bone marrow
- Spleen
- Liver (Correct answer)
- Kidneys
Correct answer: Liver
The liver synthesizes most clotting factors (I, II, V, VII, IX, X, XI, XII) as well as albumin and other plasma proteins essential for hemostasis.
The liver is the primary site of synthesis for most coagulation factors, including fibrinogen (Factor I), prothrombin (Factor II), and Factors V, VII, IX, X, XI, and XII. Liver disease impairs production of these factors, leading to prolonged PT and aPTT and increased bleeding risk.
Question 3: What does the abbreviation 'STAT' mean when written on a laboratory requisition?
- Standard test and treatment
- Specimens to arrive tomorrow
- Immediately (from Latin 'statim') (Correct answer)
- Send to alternate testing
Correct answer: Immediately (from Latin 'statim')
STAT comes from the Latin word 'statim' meaning immediately. STAT orders require the highest priority for collection, transport, and testing.
STAT (from Latin 'statim,' meaning immediately or at once) designates the highest priority laboratory order. STAT specimens must be collected immediately upon receipt of the order, transported to the laboratory without delay, and tested ahead of routine specimens. Turnaround time for STAT tests is typically 30-60 minutes.
Question 4: In the coagulation cascade, what is the final product that stabilizes a blood clot?
- Thrombin
- Fibrin (Correct answer)
- Prothrombin
- Plasmin
Correct answer: Fibrin
Fibrin is the final protein in the coagulation cascade that forms a mesh network over the platelet plug, stabilizing it into a firm blood clot.
The coagulation cascade is a series of enzymatic reactions culminating in the conversion of soluble fibrinogen (Factor I) to insoluble fibrin by the enzyme thrombin. Fibrin monomers polymerize into long strands that weave through the platelet plug, forming a mesh that stabilizes the clot.
Question 5: What is the difference between serum and plasma?
- Serum contains cells; plasma does not
- Serum lacks fibrinogen and clotting factors; plasma contains them (Correct answer)
- There is no difference between serum and plasma
- Plasma is always red; serum is always yellow
Correct answer: Serum lacks fibrinogen and clotting factors; plasma contains them
Serum is the liquid remaining after blood has clotted and fibrinogen has been consumed. Plasma is the liquid portion of anticoagulated blood that still contains fibrinogen and clotting factors.
Plasma is obtained from blood collected with an anticoagulant that prevents clotting, preserving all dissolved proteins including fibrinogen. When blood is allowed to clot, fibrinogen is converted to fibrin and incorporated into the clot. The remaining liquid is serum, which is essentially plasma minus fibrinogen and some clotting factors.
Question 6: Which type of white blood cell is most abundant in the bloodstream and first to respond to bacterial infections?
- Lymphocytes
- Monocytes
- Neutrophils (Correct answer)
- Eosinophils
Correct answer: Neutrophils
Neutrophils comprise 50-70% of all white blood cells and are the first immune cells to arrive at infection sites, where they engulf and destroy bacteria through phagocytosis.
Neutrophils are the most abundant white blood cells, constituting 50-70% of the WBC differential count. They are the immune system's first responders, migrating rapidly from the bloodstream to infection sites through chemotaxis, where they engulf bacteria through phagocytosis.
NCCT National Certified Phlebotomy Technician General 2
What is the main function of the lymphatic system in relation to blood circulation?