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Studies on immunological assay of vitamin K dependent factors.
Author(s) -
Mikami S.,
Tuddenham E. G. D.
Publication year - 1986
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1986.tb02914.x
Subject(s) - factor vii , chemistry , radioimmunoassay , polyclonal antibodies , medicine , factor x , vitamin , endocrinology , antigen , coagulation , immunology , biochemistry , platelet , thrombin
S ummary . A radioimmunoassay (RIA) for factor VII was developed using 125 I‐factor VII, anti‐factor VII rabbit serum and anti‐rabbit IgG goat serum. The lower limit of sensitivity in normal reference plasma was 3 × 10 −3 units/ml. Although the level of factor VII antigen (VII:Ag) in normal plasma samples (= 20) 0.944·0.176 units/ml. correlated with that of factor VII coagulant activity ( r = 0.89), VII:Ag level in paired normal sera showed a higher value (1.469 0.376 units/ml). The level of antigen according to RIA of factor VIIa activated by factor Xa increased 2.5‐fold compared with that of unactivated factor VII. It is suggested that the polyclonal anti‐factor VII produced in a rabbit had higher affinity for factor VIIa than for factor VII. In two out of seven patients with congenital factor VII deficiency, VII:Ag was detectable (0.04, 0.31 units/ml, respectively) whereas VII:C was less than 0.01 units/ml. In 12 warfarin‐treated individuals, VII:C showed a lower level (0.121 0.063 units/ml) that that of VII:Ag (0.518 0.186 units/ml). During 4 weeks observation after stopping warfarin, VII:C and VII:Ag reached normal levels in 1 week. However, VII:C did not reach equivalence with VII:Ag until 4 weeks had elapsed.