LUPUS ANTICOAGULANT

Test Documentation
Components
The lupus anticoagulant screen employs two screening assays, a dilute Russell Viper Venom Test (dRVVT) and a sensitive PTT (PTT-LA). If either test screens positive, it will be followed by the appropriate 1:1 mixing study. If the 1:1 mixing study remains prolonged, the appropriate confirmation test(s) will be performed (either a dRVVT confirmation, a hexagonal phase phospholipid neutralization, or both).

Specimen Required
Patient should not be on warfarin (Coumadin®) therapy for 2 weeks or heparin therapy for 2 days prior to the test. If the patient is currently on warfarin or heparin, this should be noted, as warfarin or heparin therapy can affect certain coagulation factors or assays, preclude their performance, or cause spurious results.
Draw blood in a light blue 3.2% sodium citrate tube. See appendices for coagulation test collection instructions. Send 3.0 mL plasma (2.0 mL minimum) frozen in a screw-capped plastic vial. CRITICAL FROZEN.

Rejection Criteria
Hemolyzed samples; Thawed samples

Methodology
Clotting

Stability
Room Temperature: 8 hours; Refrigerated: Unacceptable; Frozen: 1 month
CRITICAL FROZEN. Testing cannot be performed on a sample that has been thawed and refrozen.

Reference Range
Negative

Performed
Monday-Friday

Turnaround Time3 days
Test CodeLUPAC
CPT-4 Code (s)
85613 (dRVVT screen), 85730 (PTT screen), plus
85613 (dRVVT 1:1 Mix) and/or 85613 (dRVVT confirm) and/or
85598 (Hexagonal phospholipid neutralization) and/or 85732 (PTT 1:1 Mix) as appropriate
LOINC Codes
dRVVT screen   6303-2  
PTT screen   34571-0  
dRVVT confirm   57838-5  
Hexagonal phospholipid neutralization   3282-1  
PTT confirm   33930-9  
Intrpretation   3281-3  

Warde
Medical
Laboratory