A patient is admitted to the same day surgery unit for liver biopsy. Which of the following laboratory tests assesses coagulation? Select all that apply.
A. Partial thromboplastin time
B. Prothrombin time
C. Platelet count
D. Hemoglobin
E. Complete Blood Count
F. White Blood Cell Count
Correct Answer: A, B, & C
Prothrombin time, partial thromboplastin time, and platelet count are all included in coagulation studies.
Option A: PTT tests the function of all clotting factors except factor VII (tissue factor) and factor XIII (fibrin stabilizing factor). PTT is commonly used in clinical practice to monitor patient response to unfractionated heparin infusion, to target therapeutic anticoagulation, and as part of a “coagulation panel” to help elucidate causes of bleeding or clotting disorders.
Option B: Prothrombin time (PT) is one of several blood tests routinely used in clinical practice to evaluate the coagulation status of patients. More specifically, PT is used to evaluate the extrinsic and common pathways of coagulation, which would detect deficiencies of factors II, V, VII, and X, and low fibrinogen concentrations.
Option C: Clinicians can monitor the function of platelets by evaluating the bleeding time, which evaluates the time between breaking the vasculature and formation of an effective platelet plug. This time may be elevated in conditions like uremia, in which platelet count is normal but demonstrates impaired function.
Option D: A hemoglobin test measures the levels of hemoglobin in the blood. Hemoglobin is a protein in the red blood cells that carries oxygen from the lungs to the rest of the body. Hemoglobin variant testing measures by percentage, the relative hemoglobin types present in erythrocytes. This testing allows for the detection of hemoglobin variants and thalassemic disorders.
Option E: A complete blood count (CBC) is a blood test used to evaluate the overall health and detect a wide range of disorders, including anemia, infection and leukemia. A complete blood count test measures several components and features of the blood, including red blood cells, white blood cells, hemoglobin, hematocrit, and platelets.
Option F: A white blood cell (WBC) count is a test that measures the number of white blood cells in the body. Of note, if a subtype of white blood cells seems to be elevated based on the differential, the actual value of the type of white blood cells should be calculated by multiplying the percentage listed on the differential by the total number of white blood cells.