Lupus Anticoagulant (LAC)

Prenatal Screening Laboratory

Coagulation screening assays: Dilute Russell Viper Venom Test (dRVVT) and Activated Partial Thromboplastin Time (APTT)

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Specimen Required:

Refer to Special Handling Requirements

Days Test Set Up:

Run once per week

Analytic Time:

48 hours

Reference Values:

< Mean + 2SD = Negative

CPT Code(s):

85613, 85730

Relevance:

Lupus anticoagulant is associated with systemic lupus erythematosus (SLE), arterial or venous thrombosis, thrombocytopenia, recurrent pregnancy loss, postnatal maternal complications, migraine headaches, cerebrovascular accident, transient ischemic attack, or stroke.

Notes:

Patients who are positive on either screening assay are confirmed by neutralization. Clotting time is repeated with a neutralizing reagent, either hexagonal phase phopholipid or dVV Confirm^TM.

Reference(s)

• Branch DW, Scott JR, Kochenour NK, Hershgold E: Obstetric complications associated with the lupus anticoagulant. N Engl J Med, 313:1322-6, 1985.