Summary
A first clinical evaluation has been made of the performance of a newly devised immunofluorometric
assay for measuring plasma concentrations of activated protein C (APC) in complex
with protein C inhibitor (PCI). The method was compared with testing for other markers
of hypercoagulability in a case-control study comprising 123 patients with clinical
suspicion of deep vein thrombosis (DVT). The diagnosis was confirmed by ascending
phlebography, and the thrombotic burden estimated with a newly developed scoring system.
Receiver operating characteristics (ROC) curves calculated to demonstrate the discriminatory
capacity of the methods, showed the area under the curves (AUCs) to be similar for
the APC-PCI and D-dimer methods. However, in contrast to the D-dimer method, the APC-PCI
method measures a well-defined analyte, a prerequisite for reliable comparisons of
future clinical studies. The APC-PCI method appears to be particularly useful as a
marker for detection of recently developed proximal thrombi.
Keywords
APC-PCI complex - immunofluorometric assay - deep vein thrombosis - case-control study
- hypercoagulability markers