[Investigation on the incidence of high altitude polycythemia and its hemoglobin characteristics in a Tibetan population].

The incidences of high altitude polycythemia (HAPC) and its hemoglobin characteristics in natives and immigrants at 2 different altitudes in the Tibet Autonomous Region were investigated. The results were as follows: 1) The incidences of HAPC among residents in Lhasa (3650 meters above sea level) and in Naqu-Ando district (4500-4800 meters above sea-level) were 2.39% and 12.95%, respectively. The incidence of HAPC increased with increasing altitude. The incidences in immigrants and in men were higher than those in natives and in women. 2) The MetHb concentration in RBC from patients with HAPC was 10.14%, distinctly higher than that in healthy adults (6.35%) in the same area. This may be one of the causes leading to oxygen carrying malfunction in the RBCs of HAPC patients. 3) The Mossbauer spectra of RBCs from patients with HAPC had a third component "c" in addition to the two normal components, oxy-Hb "a" and deoxy-Hb "b." The third component "c" may be adenatured Hb in the RBCs of the patients. The question of whether it is related to oxygen carrying power requires further study.