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BIOS 255
March 10, 2024
Week 1 Case Study: Coagulation
1. The PT test evaluates how quickly a blood clot forms in the body and it measures the extrinsic
and common pathways of coagulation (Yang & Moosavi, 2024). This test aids in detecting
deficiencies in factors II, V, VII, X, and low fibrinogen concentrations (Yang & Moosavi, 2024). The
PTT test assesses the plasma for abnormalities in coagulation factors and measures the intrinsic
pathway of the blood clotting cascade (Rountree & Lopez, 2023). This test evaluates the
performance of all blood clotting factors, except for factors VII and XIII (Rountree & Lopez, 2023).
2. The pathway for coagulation includes two different pathways, extrinsic and intrinsic. The
extrinsic mechanism begins with the release of thromboplastin (factor III), which activates
factors VII, V, and X. The intrinsic mechanism is initiated by platelets that release factor XII, or
Hageman factor, which then cascades to factors XI, IX, VIII, and X. After activation of factor X, it
binds with factors III and V in the presence of calcium ion and PF3 to form prothrombin activator.
The prothrombin activator acts on factor II, creating thrombin. Thrombin converts fibrinogen to
fibrin, producing fibrin polymers with factor XII and calcium ions (Saladin, 2019).
3. Jessie’s test results might indicate a factor VIII deficiency, which characterizes hemophilia A
(Rountree & Lopez, 2023). Factor VIII is responsible for activating factor X in the intrinsic
pathway. Since Jessie most likely has a deficiency in this factor, the coagulation pathway cannot
be activated effectively (Saladin, 2019).
4. Jessie's clotting disease is a genetic disorder that is usually found in males. This is because it is
caused by a recessive gene that is located on the X chromosome. Since males only have one X
chromosome, they cannot offset the damage caused by this gene, as females can, who have two
X chromosomes (Rountree & Lopez, 2023).
BIOS 255
March 10, 2024
Week 1 Case Study: Coagulation
1. The PT test evaluates how quickly a blood clot forms in the body and it measures the extrinsic
and common pathways of coagulation (Yang & Moosavi, 2024). This test aids in detecting
deficiencies in factors II, V, VII, X, and low fibrinogen concentrations (Yang & Moosavi, 2024). The
PTT test assesses the plasma for abnormalities in coagulation factors and measures the intrinsic
pathway of the blood clotting cascade (Rountree & Lopez, 2023). This test evaluates the
performance of all blood clotting factors, except for factors VII and XIII (Rountree & Lopez, 2023).
2. The pathway for coagulation includes two different pathways, extrinsic and intrinsic. The
extrinsic mechanism begins with the release of thromboplastin (factor III), which activates
factors VII, V, and X. The intrinsic mechanism is initiated by platelets that release factor XII, or
Hageman factor, which then cascades to factors XI, IX, VIII, and X. After activation of factor X, it
binds with factors III and V in the presence of calcium ion and PF3 to form prothrombin activator.
The prothrombin activator acts on factor II, creating thrombin. Thrombin converts fibrinogen to
fibrin, producing fibrin polymers with factor XII and calcium ions (Saladin, 2019).
3. Jessie’s test results might indicate a factor VIII deficiency, which characterizes hemophilia A
(Rountree & Lopez, 2023). Factor VIII is responsible for activating factor X in the intrinsic
pathway. Since Jessie most likely has a deficiency in this factor, the coagulation pathway cannot
be activated effectively (Saladin, 2019).
4. Jessie's clotting disease is a genetic disorder that is usually found in males. This is because it is
caused by a recessive gene that is located on the X chromosome. Since males only have one X
chromosome, they cannot offset the damage caused by this gene, as females can, who have two
X chromosomes (Rountree & Lopez, 2023).
