In a survey on determinants of two "APC-resistance" tests, sixty healthy volunteers (mean age 41 years, range 17-60; 43 % female) were included in the study; factor V Leiden mutation, the use of oral contraceptives and hormone replacement therapy were excluded. We determine.d the levels of various clotting factors in duplicate in plasma (centrifuged twice) and tested whether a co-variation of any of these factors showed a statistically significant (Spearman) relationship with the results of the global APCresistance test (Coatest APC Resistance) or the specific APC resistance test (Coatest APC Resistance V). We observed univariate associations for the global test with prothrombin (r= -0.256; p= 0.048), factor Vila (r= 0.343; p= 0.007), factor VIII (r= -0.274; r= 0.034), factor X (r= -0.279; p= 0.031) and factor XI (r= -0.273; p= 0.035). In multivariate regression analysis the relations remained with factor Vila and factor XI; the variance in the global APC resistance data could be explained for a total of 19 %. The observations clearly illustrate that the global APC resistance test may be sensitive to variations in a number of coagulation factors and any of them can contribute to a reduced sensitivity to APC. The specific test for "APC resistance" was only associated with variations in factor V (r= 0.323; p= 0,022) and free protein S (r= 0.449; p< 0.0005), which underlines that the test design is critical in relation to the sensitivity to coagulation factors. From the above experiments we conclude that the term "APC resistance" should not be used without the exact specification of the test that determines this variable. When interesting variations are found this should result in further studies to identify the specific factors involved.
|Tidsskrift||Fibrinolysis and Proteolysis|
|Udgave nummer||SUPPL. 1|
|Status||Udgivet - 1999|