Dilute Russell's Viper Venom Time (DRVVT)

Coagulation

Description

The DRVVT is performed as part of the Lupus screen to detect antiphospholipid antibodies.

Antiphospholipid antibodies are a group of antibodies which include lupus anticoagulant, anticardiolipin antibodies (IgG or IgM) and antiβ2-glycoprotein-1 antibodies (IgG) which are associated with thrombosis and pregnancy loss/morbidity. Antiphospholipid syndrome is characterised by persistent positivity of these antibodies together with the clinical symptoms.

Lupus anticoagulant (LA) is detected by performing the DRVVT with two reagents (Screen and Confirm). Russell’s viper venom present in the screeening reagent initiates plasma clotting by directly activating factor X.. The confirmation reagent contains a high phospholipid concentration which counteracts the LA antibodies and normalises the clotting time.

Indications

Antiphospholipid antibodies can be found in patients with Antiphospholipid Syndrome either in isolation or in association with other autoimmune disorders such as systemic lupus erythematous.

Sample Type

Plasma (Citrate Blue) x 3

Reference Range

Stated on reports as a DRVVT ratio.

Turnaround Time

Within 2 weeks

Testing Frequency

Weekly

External Notes

The accuracy of all coagulation tests is greatly influenced by pre analytical variables. It is essential that sample quality is given the highest of priorities. Samples which fail to meet quality criteria including age of sample, specimen fill ( >90% ), haemolysed, clotted or activated samples will be rejected and a repeat sample requested. Samples sent frozen must be double spun before freezing.

Anticoagulation. We can test patients on Warfarin (INR stable between 1.5 – 3.0) and heparin (UFH and LMWH) if < 1.0 IU/mL. We can also test patients on direct Xa (rivaroxaban, apixaban and edoxaban) and direct IIa inhibitors (argatroban and dabigatran) through the application of a neutralisation step. Please include the patient’s anticoagulation status on the request.

Patient Preparation

No special requirements.

References

Guidelines on the investigation and management of antiphospholipid syndrome. BJH, 2012,157,47-58.

Your contact for this test

Kieron Hickey

Thrombophilia Section Lead and Deputy Laboratory Manager - Coagulation

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Dilute Russell's Viper Venom Time (DRVVT)