The detection of lupus anticoagulant using the kaolin clotting time test: a comparative study of the different forms...

This work is a report of a comparative study between the different forms of analysis (curve, index, percentage and delta) of kaolin clotting time (KCT) for the detection of lupus anticoagulant. The reference values for all tests were defined from a study of 111 normal controls. 133 patients were studied, 106 with connective tissue disease and 27 with syphilis. LA was detected in 31 of the 133 patients studied. For KCT, the percentage and the delta showed greater sensitivity (61% and 65%, respectively) as opposed to the curve and the index (48% and 26%, respectively). We found significant statistical differences between the frequency of positivity of the index and the delta (p < 0.001) and between the index and the percentage (p < 0.005). Our findings show that if it is necessary to use KCT as a complementary test for the detection of LA, then it is more convenient to carry it out by using the percentage or the delta forms of analysis.