[An improved assay for plasma tissue factor activity].
We developed an improved assay for measuring tissue factor activity in plasma with chromogenic substrate (S-2765) which is highly sensitive to factor Xa. In the ordinary assay with S-2222, it was required to prepare the euglobulin fraction of plasma and to heat it, while the improved assay required 20-fold-diluted plasma with Owren's barbital buffer (pH 7.35). The absorbance at 405nm on a colorimeter and human placental tissue thromboplastin preparation (HPT; Thromborel S, Behringwerke AG) was regressed on a semilogarithmic curve. The mean value obtained by this assay for normal subjects was 15.8 +/- 16.4 micrograms/ml HPT (mean +/- 2SD). A correlation of tissue factor activities assayed by the present method and the ordinary method was 0.62. Our data suggest that this improved assay is a useful method for measuring the plasma tissue factor activity.
Murakami
F
F
Department of Clinical Laboratory Medicine, Faculty of Medicine, Tottori University, Yonago.
Iijima
K
K
Fukuda
C
C
Ikawa
S
S
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008722:Methods; D012016:Reference Values; D013925:Thromboplastin / Q000032:analysis*
D013925:Thromboplastin