Rapid screening of PNH red cell populations using the gel test.

Paroxysmal nocturnal hemoglobinuria (PNH), an acquired clonal hematopoietic stem cell defect is underdiagnosed because of its atypical symptoms in some patients and because available methods, which are time consuming and complicated, are not widely used. The purpose of this study is to compare the results of the detection of PNH red cell populations using the PNH gel test and the Ham test. Fifty-eight blood samples obtained from 35 patients and 23 healthy blood donors were tested for PNH by the PNH gel test and the Ham test. It was found that 7 (20%) of the patients were positive for PNH by both tests. Twenty-three blood samples from healthy donors were all negative for PNH by both tests. The overall sensitivity and specificity of the gel test were 100%. This study showed that the PNH gel test was simple and could replace the Ham test as a screening test for PNH. This test would be especially easy to introduce in laboratories that are already using this system for blood grouping and antibody detection.