FRCPath Haem Part 1 EMQs-Haemostasis 13 and 14

Theme: APS

Options (Each option may be used once, more than once, or not at all)

A. Test full aPL panel (LA, aCL IgG/IgM, anti-β2GPI) now

B. Do not test for aPL

C. Repeat aPL testing after ≥12 weeks

D. Defer LA testing due to anticoagulation interference

E. Defer LA testing due to recent thrombosis/acute phase

F. Perform DRVVT and LA-sensitive APTT

G. Perform mixing study and phospholipid neutralisation step

H. Start VKA (target INR 2.0–3.0) indefinitely

I. Increase VKA intensity (target INR 3.0–4.0)

J. Discuss switching DOAC to VKA

K. Add antiplatelet therapy to VKA

L. Use DAPT instead of anticoagulation

Questions

Q1

A 44-year-old woman presents with an unprovoked proximal DVT. She has a past history of migraine and one first-trimester miscarriage.

She is started on apixaban.

Thrombophilia testing is requested by medical team on day 3 of admission. Blood sample shows:

• Prolonged APTT

• Positive DRVVT screen ratio

• Normal PT

No mixing or confirmatory studies are performed.

What is the most appropriate next step regarding APS testing?

Q2

A 39-year-old man presents with extensive iliofemoral DVT. No provoking factors are identified.

He is started on LMWH and warfarin.

Lupus anticoagulant testing is performed 5 days later upon medical team request while INR is 1.8 and anti-Xa level is therapeutic.

DRVVT is prolonged; mixing study shows incomplete correction.

What is the most appropriate interpretation/next step?

Q3

A 31-year-old woman with known SLE presents for pre-pregnancy counselling. She has no history of thrombosis but had two second-trimester miscarriages.

aPL testing shows:

• aCL IgG strongly positive

• anti-β2GPI positive

• LA negative

What is required before confirming APS diagnosis?

Q4

A 52-year-old man presents with ischaemic stroke. He has no hypertension, diabetes, or hyperlipidaemia.

aPL testing is performed 10 days after the event while he is still hospitalised and systemically unwell.

LA is weakly positive

What is the most appropriate next step?

Q5

A 47-year-old woman with triple-positive APS presents with recurrent DVT while on warfarin with consistently therapeutic INR (2.3–2.7).

Adherence is confirmed. No malignancy identified.

What is the most appropriate management change?

Q6

A 36-year-old man with triple-positive APS and prior PE is treated with rivaroxaban by medical team.

He prefers DOAC due to lifestyle convenience.

He has had no recurrence over 18 months.

What is the most appropriate recommendation?

Q7

A 58-year-old woman with APS presents with acute ischaemic stroke.

She has a history of hypertension and smoking.

She is commenced on warfarin (INR target 2–3).

What additional therapy should be considered given her vascular risk profile?

Q8

A 62-year-old man with APS presents with stroke but has a recent intracranial haemorrhage making anticoagulation unsafe.

What is the most appropriate alternative strategy?

Q9

A 41-year-old man is referred for APS testing after a PE that occurred following prolonged immobilisation after a road traffic accident.

He has fully recovered and is otherwise well.

What is the most appropriate approach?

Q10

A 45-year-old woman with APS is planned for warfarin therapy.

Baseline PT is prolonged before starting anticoagulation.

What is the most appropriate action?