[Experiences in clinical diagnosis of paroxysmal nocturnal hemoglobinuria (PNH)].

Two hundred and three cases of PNH diagnosed (according to the National Unified Diagnosed Criteria, 1987) and treated from 1949 to 1992 in Peking Union Medical Hospital were analyzed retrospectively in an attempt to investigate the factors leading to delayed diagnosis. The presenting manifestation was anemia in 56.7% of the patients. Next was hemorrhage (24.6%). Hemoglobinuria was seen only in 12.8% of the cases at the onset. Ham test was persistently negative in 10.4% of the patients. Only one third of all the cases was correctly diagnosed as PNH within one year after onset. Aplastic anemia or anemia of unknown cause was first diagnosed in 60.1% of cases. The heterogeneity of the manifestations and the lack of sensitive and also specific laboratory tests were the factors leading to delayed diagnosis, but negligence of PNH in differential diagnosis seem to be a major the main cause. Constant awareness of the possibility and careful follow-up accompanied with repeated laboratory examinations in a suspected case are crucial for early diagnosis of PNH.