Original ArticlesA new method to measure plasma levels of activated protein C in complex with protein C inhibitor in patients with acute coronary syndromesStrandberg, K.; Bhiladvala, P.; Holm, J.; Stenflo, J.Author Information K. Strandberg and J. Stenflo are with the Department of Clinical Chemistry, and P. Bhiladvala and J. Holm are with the Department of Cardiology, University Hospital, Malmö, Lund University, Malmö, Sweden. (Received 23 March 2001; revised 24 May 2001; accepted 24 May 2001) Sponsorship: This work was supported by grants from the Swedish Medical Research Council (Nos. B96-03X-04487-22B, B96-03X-10825-03A), the Swedish Foundation of Strategic Research, the Kock Foundation, the Påhlsson Foundations, and the Foundation of University Hospital, Malmö. Address correspondence to Professor Johan Stenflo, Department of Clinical Chemistry, University Hospital, Malmö, Lund University, S-205 02 Malmö, Sweden. Tel: +46 40 331421; fax: +46 40 929023; e-mail: firstname.lastname@example.org Blood Coagulation & Fibrinolysis: October 2001 - Volume 12 - Issue 7 - p 503-510 Buy Abstract Our newly devised immunofluorometric sandwich assay for measuring plasma concentrations of activated protein C (APC) in complex with protein C inhibitor (PCI) was compared with testing for conventional markers of myocardial damage CKMB (creatine kinase MB), TNI (troponin I) and hypercoagulability (D-dimer, TAT) in 76 patients with suspected myocardial infarction (MI). APC–PCI complex levels in samples drawn on admission did not correlate with CKMB in the simultaneously drawn sample but correlated closely with maximal CKMB, which reflects MI size (r = 0.52). The areas under the receiver operating characteristics (ROC) curves calculated for the APC–PCI complex results obtained upon admission did not differ significantly from the corresponding values for CKMB, TNI or TAT. Our results show that in patients at risk for MI, the APC–PCI concentration is a sensitive and independent marker that can identify a subgroup of MI patients with normal CKMB but an increased APC–PCI level upon admission. It remains to be determined whether these patients would benefit from early intensive anticoagulant treatment. © 2001 Lippincott Williams & Wilkins, Inc.