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 (R) image cytometer (Nanoentek Inc., Seoul, Korea) was developed for image-based cellular analysis. In this study, we detected PMAs with the ADAM (R) cytometer, evaluated the reproducibility of the measurements made by the ADAM (R) cytometer, and compared the abilities of the ADAM (R) 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 (R) cytometer in order to assess the reproducibility of its measurements. To compare the ability of the ADAM (R) 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 (R) cytometer showed good reproducibility (CV < 10% for all specimens). Moreover, the PMA measurements made by the ADAM (R) cytometer exhibited a high correlation with those made by a flow cytometric assay (R = 0.944). Conclusions: The ADAM (R) 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 (R) 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.