Point-of-care testing in critically ill patients

Point-of-care (POC) testing in hemostasis has experienced a significant increase in the spectrum of available tests and the number of tests performed. Short turn-around time and observation of rapid changes in test results are facilitated. The quality control process in POC testing must encompass a preanalytic (collection), analytic (measurement), and postanalytic (clinical response) phase. Erroneous interpretation of findings and difficult quality controls can outweigh the advantages of POC testing.Only a limited number of hemostatic POC tests have proven useful so far: prothrombin time POC-monitoring of oral vitamin K antagonists; activated clotting time POC-monitoring of high-dose heparin therapy; platelet function analyzer (PFA; Siemens, Marburg, Germany) closure time (CT)-detection of von Willebrand disease and severe platelet function defects; whole blood aggregometry (WBA) Multiplate (Roche Diagnostics, Rotkreuz, Switzerland), and the VerifyNow system (Accumetrics, San Diego, CA)-detection of platelet dysfunction due to antiplatelet drugs; thromboelastography-continuous observation of clot formation and fibrinolysis. The use of various agonists in WBA and thromboelastography (TEG) requires some expertise. In experienced hands the PFA CT and WBA and TEG are recommended combinations.Application of POC testing depends strictly on whether it improves medical care and patient outcome. More POC test systems are in the research pipeline, but only a few will resist the ravages of time.