Immunoturbidimetric assay for rheumatoid factor using an enzyme immunoassay microplate reader.

receiving full dose heparin (A kaolin clotting time; 56, 29, and 19 seconds) and four had been considered to have equivocal lupus inhibitor tests. On testing of subsequent samples from three of the equivocal patients, one with a A kaolin clotting time of 29 seconds was found to have a definite lupus inhibitor while the two others (19 and 14 seconds) were negative. The A kaolin clotting time in the two positive patients with normal PTTKs was 14 and 34 seconds and in the positive patients with normal APTTs the A kaolin clotting time range was 14-150 seconds with a mean (SD) of 24-6 (21-6) seconds.