Platelet Aggregation Testing on a Routine Coagulation Analyzer: A Method Comparison Study

Platelet function (PF) plays a pivotal role in both hemostasis and thrombosis, and manual light transmission aggregometry (LTA) is considered the standard of care for platelet function testing but is an error-prone and time-consuming procedure. We aimed to test the agreement regarding maximum aggregation (MA), velocity (VEL), and lag-phase (LagP) of platelet aggregation of the automated Sysmex CS-2100i analyzer (Siemens, Germany) against the APACT 4004 (Elitech, France) in samples derived from healthy participants and patients with hemostaseologic disorders. In total, 123 patient-derived samples were investigated, including 42 patients with acetylsalicylic acid and/or clopidogrel intake and 20 patients with other hemostaseologic disorders. Both MA and VEL showed good or excellent intermethod correlation. Agreement between the testing methods was only partially achieved, and values were indicative for a systematic bias to lower measurements below a threshold of 50% MA with the CS-2100i compared to the APACT 4004. All patients with impaired PF in the APACT 4004 were successfully identified with the CS-2100i, and reference values for automated LTA are provided. Conclusively, automated LTA with the CS-2100i is a highly standardized and reliable PF testing method and represents a decisive step in the simplification of platelet function testing in clinical routine.