Coagulation questions for the DHA hematology scientist exam.
Coagulation at the clinical scientist level covers the physiology of hemostasis and fibrinolysis, the principles and pitfalls of coagulation tests, inherited and acquired bleeding and thrombotic disorders, and anticoagulant monitoring. Candidates for this DHA specialist exam should be able to interpret complex test patterns and recommend the most informative further investigations.
Free · no card needed · every answer explained
159
coagulation practice questions
- 20%
- of the exam
- 8
- subtopics
- Oct 2026
- updated
Inside this topic.
The subtopics our coagulation questions cover.
- Factor Deficiencies
- Methodology
- Monitoring
- Mixing Studies
- Biochemistry
- Thrombophilia
- Troubleshooting
- Platelet Disorders
Key facts to remember.
High-yield coagulation points to revise before the exam.
- 1
An isolated prolonged APTT that corrects on a 50:50 mix with normal plasma suggests a factor deficiency, whereas failure to correct suggests an inhibitor such as lupus anticoagulant.
- 2
Lupus anticoagulant testing uses two tests based on different principles, typically dRVVT and a sensitive APTT, each with screening, mixing and confirmation steps.
- 3
Unfractionated heparin is monitored with the APTT or an anti-Xa assay, while low molecular weight heparin, when monitoring is needed, requires an anti-Xa assay.
- 4
Von Willebrand disease is assessed with VWF antigen, VWF activity and factor VIII; an activity-to-antigen ratio below about 0.6-0.7 suggests a qualitative (type 2) defect.
- 5
Citrate tubes must give a 9:1 blood-to-citrate ratio, and a hematocrit above 55% requires the citrate volume to be reduced to avoid falsely prolonged clotting times.
Sample questions with answers.
10 practice questions for the Hematology - Clinical Scientist - DHA Healthcare Professional Licensing (Coagulation). Pick an answer to see if you're right, with a full explanation.
Question 1
The "Reptilase Time" is useful in coagulation testing because it is NOT inhibited by:
Question 2
A patient with "Type 1 von Willebrand Disease" is scheduled for a minor dental procedure. Which treatment is most appropriate to transiently raise vWF and Factor VIII?
Question 3
A patient with Hemophilia A has developed an "Inhibitor." What is the expected result of a 1:1 Mixing Study?
Question 4
What is the primary function of "Vitamin K" in the coagulation cascade?
Question 5
The "International Normalized Ratio" (INR) is calculated using which formula?
Question 6
A new lot of APTT reagent arrives. How many "normal" donor samples are typically required to establish a new Mean Normal Prothrombin Time (MNPT) or APTT Mean?
Question 7
A patient with a Hct of 65% is sampled for a PT/APTT. The technician must adjust the citrate volume. What is the effect if the volume is NOT adjusted?
Question 8
A patient with "Afibrinogenemia" will have which of the following results?
Question 9
In a case of "Disseminated Intravascular Coagulation" (DIC), which of the following is typically "Decreased"?
Question 10
A patient has a 'Prolonged PT' and 'Prolonged APTT'. Which factor deficiency would NOT cause this?
Other topics in this exam.
Questions, answered
Compare the immediate and incubated (typically 1-2 hours at 37°C) mixes with normal plasma. Correction of both suggests a factor deficiency, while correction immediately but prolongation after incubation suggests a time-dependent inhibitor such as an acquired factor VIII inhibitor; lupus anticoagulant usually fails to correct immediately. Use a defined correction criterion, such as the index of circulating anticoagulant, rather than a visual judgement.
Direct oral anticoagulants prolong the PT and APTT to variable degrees and can cause false-positive lupus anticoagulant results, particularly with dRVVT. Drug levels are measured with calibrated anti-Xa assays for rivaroxaban, apixaban and edoxaban, and with a dilute thrombin time or ecarin-based assay for dabigatran. The time of the last dose relative to sampling is essential for interpretation.
Ready to practise coagulation?
All 159 coagulation questions, with explanations and a readiness score for this topic.