A 4-year-old girl whose parents are first cousins has had long nosebleeds since infancy and now has a swollen, painful ankle after a minor fall. Results: platelets 310 × 10^9/L, PT 12.0 s (reference 11.0-13.5 s), APTT 58 s (25-35 s), corrected in a 1:1 mix; factor VIII 4 IU/dL, VWF antigen below 3 IU/dL and VWF activity (GPIbM) below 3 IU/dL (all reference 50-150). No VWF multimers are seen. Neither parent has a bleeding history; their VWF antigen levels are 48 and 55 IU/dL. The most likely diagnosis is:

Severe type 1 von Willebrand disease

A 7-year-old boy has a hot, swollen right knee after a minor fall at school. His maternal grandfather had 'hemophilia' of unknown type, and his mother has never been tested. Results: platelets 290 × 10^9/L, PT 12.4 s (reference 11.0-13.5 s), APTT 61 s (25-35 s), corrected in both an immediate and a 2-hour incubated 1:1 mix; factor VIII 94 IU/dL, factor IX 3 IU/dL and factor XI 88 IU/dL (all reference 50-150), with normal VWF antigen and activity. The orthopedic team asks which product to give for the joint bleed. The most appropriate product is:

Recombinant factor IX concentrate

Recombinant factor VIII concentrate

Why is factor VIII activity often low in type 3 von Willebrand disease, although the factor VIII gene is normal?

Without VWF, factor VIII is cleared quickly from plasma

VWF is needed to switch on factor VIII gene expression

The VWF and factor VIII genes are inherited together

Antibodies to VWF also neutralize factor VIII

By ISTH criteria, hemophilia is graded as moderate when the baseline factor activity is:

Below 1 IU/dL (below 0.01 IU/mL)

Hemophilia and von Willebrand disease

15 DOH Abu Dhabi (HAAD) lab licensing practice questions on Hemophilia and von Willebrand disease, part of Coagulation and Hemostasis. The first 15 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 4-year-old girl whose parents are first cousins has had long nosebleeds since infancy and now has a swollen, painful ankle after a minor fall. Results: platelets 310 × 10^9/L, PT 12.0 s (reference 11.0-13.5 s), APTT 58 s (25-35 s), corrected in a 1:1 mix; factor VIII 4 IU/dL, VWF antigen below 3 IU/dL and VWF activity (GPIbM) below 3 IU/dL (all reference 50-150). No VWF multimers are seen. Neither parent has a bleeding history; their VWF antigen levels are 48 and 55 IU/dL. The most likely diagnosis is:
1. AModerate hemophilia A
2. BType 3 von Willebrand disease
3. CSevere type 1 von Willebrand disease
4. DType 2N von Willebrand disease
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Answer: B · Type 3 von Willebrand disease
VWF antigen and activity are both undetectable and no multimers are present, which is the virtual absence of VWF that defines type 3 VWD. It is autosomal recessive, so healthy consanguineous parents who are heterozygous carriers with low-normal VWF fit well. Factor VIII is low because VWF normally carries it and protects it from rapid clearance, which explains the joint bleed as well as the mucosal bleeding. In hemophilia A and in type 2N VWD the VWF antigen and multimers are normal, and in type 1 VWD VWF is reduced but still detectable, with all multimer sizes. Desmopressin does not work in type 3; bleeding is treated with a VWF-containing concentrate.
- A: Hemophilia A leaves VWF normal and is rare in girls; here VWF is absent.
- C: Type 1 has reduced but detectable VWF, with all multimer sizes present.
- D: Type 2N has normal VWF antigen and multimers but poor factor VIII binding.
Question 2 · Hard
A 7-year-old boy has a hot, swollen right knee after a minor fall at school. His maternal grandfather had 'hemophilia' of unknown type, and his mother has never been tested. Results: platelets 290 × 10^9/L, PT 12.4 s (reference 11.0-13.5 s), APTT 61 s (25-35 s), corrected in both an immediate and a 2-hour incubated 1:1 mix; factor VIII 94 IU/dL, factor IX 3 IU/dL and factor XI 88 IU/dL (all reference 50-150), with normal VWF antigen and activity. The orthopedic team asks which product to give for the joint bleed. The most appropriate product is:
1. ADesmopressin (DDAVP)
2. BRecombinant factor IX concentrate
3. CCryoprecipitate
4. DRecombinant factor VIII concentrate
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Answer: B · Recombinant factor IX concentrate
The APTT corrects with normal plasma in both mixes, so this is a deficiency, not an inhibitor, and the only low factor is IX at 3 IU/dL: moderate hemophilia B (1-5 IU/dL by ISTH criteria). The X-linked pattern fits: every daughter of an affected man inherits his X chromosome, so his mother is an obligate carrier. Factor IX concentrate, recombinant or plasma-derived, is the treatment of choice for a hemarthrosis. Cryoprecipitate contains fibrinogen, factor VIII, VWF and factor XIII but almost no factor IX, and desmopressin releases only VWF and factor VIII from endothelial stores. Factor VIII concentrate would treat hemophilia A, which his normal factor VIII excludes.
- A: Desmopressin raises VWF and factor VIII, not factor IX.
- C: Cryoprecipitate has fibrinogen, factor VIII, VWF and factor XIII, but almost no factor IX.
- D: Factor VIII is normal; the missing factor is IX.
Question 3 · Medium
Why is factor VIII activity often low in type 3 von Willebrand disease, although the factor VIII gene is normal?
1. AVWF is needed to switch on factor VIII gene expression
2. BThe VWF and factor VIII genes are inherited together
3. CWithout VWF, factor VIII is cleared quickly from plasma
4. DAntibodies to VWF also neutralize factor VIII
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Answer: C · Without VWF, factor VIII is cleared quickly from plasma
In plasma, factor VIII circulates bound to VWF, which protects it from proteolysis and early clearance. Free factor VIII is cleared within a few hours, while VWF-bound factor VIII has a half-life of about 12 hours. With almost no VWF, factor VIII falls to roughly 1-10 IU/dL although it is made normally; the same mechanism lowers it in type 2N, where VWF cannot bind factor VIII.
- A: VWF does not control factor VIII gene expression.
- B: The VWF gene is on chromosome 12 and the factor VIII gene is on the X chromosome.
- D: Type 3 VWD is a lack of VWF, not an antibody disorder.
Question 4 · Easy
By ISTH criteria, hemophilia is graded as moderate when the baseline factor activity is:
1. ABelow 1 IU/dL (below 0.01 IU/mL)
2. B1-5 IU/dL (0.01-0.05 IU/mL)
3. C40-60 IU/dL (0.40-0.60 IU/mL)
4. DAbove 5 and below 40 IU/dL
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Answer: B · 1-5 IU/dL (0.01-0.05 IU/mL)
The ISTH grades hemophilia A and B by baseline factor VIII or IX activity: severe below 1 IU/dL, moderate 1-5 IU/dL, and mild above 5 and below 40 IU/dL. Moderate patients bleed mainly after minor injury and sometimes spontaneously, while severe patients have spontaneous joint and muscle bleeds. Grading guides how often bleeding is expected and how prophylaxis is planned.
- A: Below 1 IU/dL is severe hemophilia.
- C: A level of 40 IU/dL or more is not graded as hemophilia.
- D: Above 5 and below 40 IU/dL is mild hemophilia.
Question 5 · Medium
A 30-year-old man with lifelong mucosal bleeding has VWF antigen 38 IU/dL, VWF activity 15 IU/dL (both reference 50-150) and factor VIII 48 IU/dL. Multimers show loss of the large and intermediate forms. Which type of VWD fits best?
1. AType 2N
2. BType 2M
3. CType 2A
4. DType 1
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Answer: C · Type 2A
An activity-to-antigen ratio below 0.7 points to a qualitative (type 2) defect; here it is 15 ÷ 38, about 0.4. Loss of the large and intermediate multimers, which carry most of the platelet-binding activity, identifies type 2A, the most common type 2 variant. Type 2B also loses large multimers but shows increased aggregation with low-dose ristocetin.
- A: Type 2N has a low factor VIII with normal VWF activity and antigen.
- B: Type 2M has a low ratio but a normal multimer pattern.
- D: Type 1 has a ratio of 0.7 or more and all multimer sizes present.
Question 6 · Medium
A 6-year-old boy with severe hemophilia A has had no recent treatment. Which set of results is expected?
1. ANormal APTT, long PT, normal PFA closure time
2. BLong APTT, long PT, long PFA closure time
3. CLong APTT, normal PT, long PFA closure time
4. DLong APTT, normal PT, normal PFA closure time
Answer and explanation in LearnFree account
Question 7 · Hard
A 3-day-old boy oozes from his heel-prick site, and his maternal uncle has hemophilia A. The APTT is prolonged for his age, the PT is normal for age and factor VIII is 4 IU/dL (adult reference 50-150). What is the best interpretation?
1. AModerate hemophilia A; factor VIII is near adult levels at birth
2. BVitamin K deficiency bleeding; give vitamin K and retest
3. CNormal for a newborn; repeat the factor VIII at 6 months
4. DMild hemophilia A; neonatal factor VIII runs low
Answer and explanation in LearnFree account
Question 8 · Hard
Desmopressin (DDAVP) is being considered before minor surgery. Which patient is the best candidate for it?
1. AA woman with type 3 VWD (VWF undetectable)
2. BA boy with severe hemophilia B (factor IX < 1 IU/dL)
3. CA man with mild hemophilia A (factor VIII 20 IU/dL)
4. DA woman with type 2B VWD and low platelets
Answer and explanation in LearnFree account
Question 9 · Medium
A woman's father has severe hemophilia B. Her partner is unaffected, and prenatal testing shows she is carrying a boy. What is the chance that this boy has hemophilia B?
1. A0%
2. B25%
3. C50%
4. D100%
Answer and explanation in LearnFree account
Question 10 · Easy
Most of the von Willebrand factor in plasma is made by:
1. AMonocytes
2. BFibroblasts
3. CEndothelial cells
4. DHepatocytes
Answer and explanation in LearnFree account
Question 11 · Hard
A 5-year-old boy bled for a day after a tonsillectomy. APTT is 42 s (reference 25-35 s), PT is normal and factor VIII is 18 IU/dL (reference 50-150). There is no family history. Before mild hemophilia A is diagnosed, which tests are most needed?
1. AVWF antigen and VWF activity
2. BPlatelet aggregation studies
3. CFactor IX and factor XI assays
4. DA Bethesda inhibitor assay
Answer and explanation in LearnFree account
Question 12 · Medium
A 17-year-old with heavy periods and nosebleeds has normal VWF antigen, VWF activity and factor VIII. The sample was taken in the emergency department soon after a fall, while she was distressed. What is the best next step?
1. AMeasure factor IX activity on this sample
2. BRequest VWF multimer analysis on this sample
3. CReport that VWD has been excluded
4. DRepeat the VWF tests later when she is well
Answer and explanation in LearnFree account
Question 13 · Hard
A 79-year-old woman with severe aortic stenosis has recurrent gastrointestinal bleeding from angiodysplasia and no earlier bleeding history. VWF antigen is 92 IU/dL and VWF activity 41 IU/dL (both reference 50-150), and multimers show loss of the largest forms. The most likely explanation is:
1. ALate-onset inherited type 2A VWD
2. BType 2B VWD with spontaneous platelet binding
3. CType 1 VWD unmasked by older age
4. DAcquired VWD from shear-induced VWF cleavage
Answer and explanation in LearnFree account
Question 14 · Medium
In the hemophilia A pedigree shown, the family member who must be a carrier (an obligate carrier) is:
Figure: MedExams
1. AI-2
2. BII-3
3. CIII-2
4. DII-1
Answer and explanation in LearnFree account
Question 15 · Hard
Which result pattern best fits type 1 von Willebrand disease?
1. AA low platelet count, whatever the subtype
2. BLow fibrinogen with normal VWF levels
3. CProlonged PT only, with a normal aPTT and normal PFA time
4. DLow VWF antigen and activity, long PFA closure time
Answer and explanation in LearnFree account

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Hemophilia and von Willebrand disease

Why is factor VIII activity often low in type 3 von Willebrand disease, although the factor VIII gene is normal?

By ISTH criteria, hemophilia is graded as moderate when the baseline factor activity is:

A 30-year-old man with lifelong mucosal bleeding has VWF antigen 38 IU/dL, VWF activity 15 IU/dL (both reference 50-150) and factor VIII 48 IU/dL. Multimers show loss of the large and intermediate forms. Which type of VWD fits best?

A 6-year-old boy with severe hemophilia A has had no recent treatment. Which set of results is expected?

A 3-day-old boy oozes from his heel-prick site, and his maternal uncle has hemophilia A. The APTT is prolonged for his age, the PT is normal for age and factor VIII is 4 IU/dL (adult reference 50-150). What is the best interpretation?

Desmopressin (DDAVP) is being considered before minor surgery. Which patient is the best candidate for it?

A woman's father has severe hemophilia B. Her partner is unaffected, and prenatal testing shows she is carrying a boy. What is the chance that this boy has hemophilia B?

Most of the von Willebrand factor in plasma is made by:

A 5-year-old boy bled for a day after a tonsillectomy. APTT is 42 s (reference 25-35 s), PT is normal and factor VIII is 18 IU/dL (reference 50-150). There is no family history. Before mild hemophilia A is diagnosed, which tests are most needed?

A 17-year-old with heavy periods and nosebleeds has normal VWF antigen, VWF activity and factor VIII. The sample was taken in the emergency department soon after a fall, while she was distressed. What is the best next step?

A 79-year-old woman with severe aortic stenosis has recurrent gastrointestinal bleeding from angiodysplasia and no earlier bleeding history. VWF antigen is 92 IU/dL and VWF activity 41 IU/dL (both reference 50-150), and multimers show loss of the largest forms. The most likely explanation is:

In the hemophilia A pedigree shown, the family member who must be a carrier (an obligate carrier) is:

Which result pattern best fits type 1 von Willebrand disease?