Table 2.

ISTH Criteria for lupus anticoagulant detection (compiled from references (19, 21, 22)).

• Prolongation of a phospholipid-dependent clotting assay. Two tests based on different assay principles should be used (e.g., the dRVVT and aPTT).

• Evidence of inhibitory activity on mixing tests with normal pooled plasma. A 1:1 proportion of patient and normal pooled plasma, without preincubation, should be used.

• Evidence that inhibitory activity is phospholipid-dependent. Confirmatory testing should be performed by increasing the concentration of phospholipid in the screening test(s) that was abnormal.

• Differentiation from other coagulopathies that may give similar laboratory results or may occur concomitantly with lupus anticoagulants. Specific factor assays may be necessary to accomplish this step.