Thrombophilia testing

Definition/Description

In most occasions of thrombosis, thrombophilia screening will not be indicated (these tests are poor at determining risk of recurrence of VTE and do not alter clinical management).

Red Flag Symptoms

None

Guidelines on Management

Generally, if anti-coagulant or clinical management will change because of the test result from the thrombophilia screen, then testing may well be indicated.

A limited screen for acquired thrombophilia is more likely to have impact on management when tested in certain circumstances below (this includes PNH – paroxysmal nocturnal haemoglobinuria, MPN panel – myeloproliferative neoplasm and APL – anti-phospholipid testing)

Thrombosis at unusual sites
- Splanchnic or CSVT – MPN, APL
- Abnormal FBC – PNH, MPN
Unprovoked VTE – APL
Recurrent thrombosis on anticoagulation – PNH, APL, MPN
Selective testing of 1st degree relatives with protein C, S and Anti-thrombin – see guideline
Retinal vein occlusion with no risk factors – APL
Arterial thrombosis
- With no risk factors – APL
- With abnormal FBC – MPN, PNH
CVA
- Less than 50 with no risk factors – APL
- With abnormal FBC – PNH, MPN
Purpura fulminans or warfarin induced skin necrosis – protein C, S
Neonates with multiple unexplained thrombosis – APL, heritable thrombophilia screen
Pregnancy associated thrombosis
- Anti-thrombin testing if family history of anti-thrombin deficiency or heparin resistance
- APL, test when not pregnant
- Recurrent or late pregnancy loss - APL

When to test?

Avoid testing in the acute post-thrombotic period - delay testing for 3 months Wherever possible avoid testing while on anticoagulant drugs (Warfarin, UFH, DOAC) - delay testing.
PNH, MPN panel, anti-cardiolipin and anti B2-glycoprotein may be tested on anticoagulation where possible in primary care
Avoid testing during pregnancy, delay testing for 2 months.

If in doubt please discuss requests for thrombophilia screening with a Consultant Haematologist or Senior BMS.