Lupus anticoagulant

Alphabetical Test listing

Lupus anticoagulant-5751

Lupus anticoagulant
Lupus inhibitor assay

Positive results will reflex to additional testing.

Sodium citrate (Na cit) plasma

 Lt blue Sodium citrate (Na Cit) - 2.7mL

If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube.

Hematocrit-Anticoagulant adjustments

1.5 mL
  • Do not draw immediately following a heparin dose.
  • Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical

Coag – tube fill guidelines

  • Immediatley following collection, mix sample thoroughly by gentle inverting 8 - 10 times, to prevent clotting

Frozen (strict)

  • Patients on heparin > 1.0 IU/mL, warfarin, DOACs, Lepirudin, or Argatroban
  • Improper labeling (unlabeled or mislabeled)
  • Improper anticoagulant
  • Improperly filled tube
  • Hemolysis
  • Clotted specimen
  • Delay in transport
  • Improper storage/transport temperature
AHL - Coagulation/Special Coagulation: V
Mo - Fr
2 days

Clot based assay

STACLOT confirmatory test: Phospholipid/Hexagonal Phase Phosphatidylethanolamine (HPE)



PTT-LA:        ≤ 43.9 seconds
DRVVT ratio: < 1.20


Lupus anticoagulant testing results may be falsely positive in patients on anticoagulant therapy. We recommend disregarding results obtained while patient is on any form of anticoagulant. Consider consulting with Anticoagulant and Thrombophilia Clinic at 612-863-6800.

The diagnosis of antiphospholipid syndrome requires two positive Lupus anticoagulant test results, obtained at least 12 week apart, which have preferably been performed when the patient is off anticoagulation therapy. Testing for Cardiolipin antibodies (661) and Beta-2 glycoprotein 1 antibodies (7769) is strongly recommended.

Note that different PT/INR reagents available for use in labs have significant variability in their sensitivity to Lupus anticoagulants. In general, only 10-15% of Lupus anticoagulants affect the INR, leading to falsely elevated INR levels. Only in those limited cases would monitoring warfarin therapy by Chromogenic factor X (5767) levels be appropriate. Otherwise, PT/INR would still be the right test for monitoring patients with normal baseline INR.

85730 - PTT-LA
85613 - DRVVT screen

Additional CPT codes (if appropriate):
85598 - STACLOT LA
85613 - DRVVT confirm