FLAER-negative CD15+ neutrophils can be used for the simplified screening of suspected PNH cases.

BACKGROUND: The flow cytometry analysis of GPI-linked proteins on red blood cells and leukocytes is crucial for paroxysmal nocturnal hemoglobinuria (PNH) diagnostics. However, the commonly used multicolor panels cannot be implemented in low-resourced hematology laboratories. In order to develop a simple prediagnostic test for PNH screening, we analyzed the diagnostic accuracy of the two-color (FLAER/CD15) detection of GPI-deficient neutrophils. METHODS: We reanalyzed multicolor data set of 1594 peripheral blood samples of patients screened for PNH applying only two markers (FLAER/CD15). The quantitative positivity/negativity was reported. Then, these results were compared in a blinded manner with previously obtained multicolor data from the same samples. RESULTS: Among the 1594 samples included in the study, 507 samples were PNH-positive by the multicolor assay. The two-color method revealed 510 PNH-positive samples. The detailed examination of this discrepancy revealed 12 false-positives and 9 false-negatives. Therefore, FLAER/CD15 screening method displayed 98.90% of the diagnostic specificity and 98.22% of the sensitivity. CONCLUSION: This simple two-color evaluation of FLAER-negative neutrophils is a highly effective screening test for PNH. Although this approach is not intended to replace the multicolor diagnostic procedure, it could minimize the number of patients requiring a conventional multicolor flow cytometric assay.