Estimates of the components of variation of a number of coagulation factor assays
are presented and are compared with those for other haematological and biochemical
variables. They have been derived from a study in which fourteen volunteers gave blood
samples approximately bi-monthly for three years. The systematic between-batch variation
w7as generally only a small component of the total variation. However, the proportion
of the total variation due to differences between people ranged from about 15% in
the case of two measures of antithrombin III to about 85% for cholesterol and haemoglobin.
For factor VII activity and fibrinogen, the figure was just over 70%. These estimates
of the components of variation are not generally available in the literature. In view
of the increasing interest in the role of coagulation factors in the pathogenesis
of arterial disease, estimates of this kind are needed both for the interpretation
of observed relationships as well as for planning sample sizes for future studies.
Keywords
Coagulation factors - Components of variability
