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Inhibitor assay (Nijmegen Bethesda)

Category Haematology Haematology >> Specialised Coagulation Services
Test background

An inhibitor quantification may be undertaken after inhibitor screen is positive or as a first line test if there is a strong suspicion of inhibitor development. Inhibitors are formed in an individual with inherited deficiency of FVIII or FIX after exposure to specific clotting factors.

Inhibitors formation can also be acquired and formed against one’s own FVIII usually in auto-immune conditions such as SLE, Rheumatoid Arthritis and neoplasms.

The Inhibitor Assay (Bethesda) uses the Nijmegen modification to quantify inhibitor activity in Bethesda Units (BU).

Clinical Indications

Inhibitor quantification may be necessary if a patient has a poor clinical response to concentrate or lower FVIII/FIX recovery after treatment with concentrates.

To monitor inhibitor development in patient with mild or moderate haemophilia

Acquired FVIII deficiency

Reference range

Normal level = < 0.7 BU

Sample & container required 2.7 mL sodium citrate (pale blue top) adults; 1.8 mL sodium citrate (pale blue top) paediatrics
Turnaround time 14 days

Please Note: Samples will be rejected if under/over-filled, clotted or haemolysed.

The laboratory is not UKAS accredited for this test due to a change in equipment/assay. Awaiting assessment.