Modification of functional serum antithrombin III assay for fibrometer. Results of examination of 50 patients.

The functional antithrombin III assay of von Kaulla is described and modified for the fibrometer with substitution of readily available Owren's buffer for previously described buffers. The assay is compared with immunological techniques on 50 hospital patients and comparable discrimination of normals and patients with thrombotic disease are shown. Normal values are 51.1+/-13.9 secs. Results in patients with thrombotic diseases are 16.7+/-1.8 secs.