Detection of platelet-monocyte aggregates by the ADAM(®) image cytometer.

Background: Inappropriate platelet activation is known to be associated with various thrombotic disorders. Platelet-monocyte aggregates (PMAs), whose formation is mediated by platelet surface P-selectin (CD62P), can be used as a reliable marker to detect platelet activation. Previous studies have generally detected PMAs through flow cytometry-based approaches. Recently, the ADAM® image cytometer (Nanoentek Inc., Seoul, Korea) was developed for image-based cellular analysis. In this study, we detected PMAs with the ADAM® cytometer, evaluated the reproducibility of the measurements made by the ADAM® cytometer, and compared the abilities of the ADAM® cytometer and a flow cytometric assay to detect PMAs. Methods: Whole blood samples were collected from patients. Within 5 minutes of collection, anticoagulated whole blood samples were fixed in 10% paraformaldehyde and 5% glyoxal. Nineteen clinical specimens were collected; each was analyzed three times with the ADAM® cytometer in order to assess the reproducibility of its measurements. To compare the ability of the ADAM® cytometer with that of a flow cytometer to detect PMAs, each cytometer was used for 23 clinical samples and the correlation of the measurements was determined. Results: The PMA measurements made by the ADAM® cytometer showed good reproducibility (CV < 10% for all specimens). Moreover, the PMA measurements made by the ADAM® cytometer exhibited a high correlation with those made by a flow cytometric assay (R = 0.944). Conclusions: The ADAM® cytometer is a suitable alternative method to the flow cytometry-based assays. Since the ADAM cytometer does not need specialized instrument knowledge or software proficiency (unlike flow cytometry), the ADAM® cytometer can be used as a rapid and reliable POCT device to measure platelet activation in peripheral blood. This, in turn, will provide valuable information regarding patient propensities to thrombotic diseases.