Normal hematological values for healthy persons living at 4000 meters in Bolivia.

Defining the range of normal hematocrit and hemoglobin levels in residents of high altitude is required to diagnose chronic mountain sickness (CMS) and other conditions defined, in part, by hematocrit or hemoglobin values. We studied 1,934 healthy, young (aged 15 to 29 yr) male and female residents of Potosí, Bolivia (4000 m), to determine the average and normal range of hemoglobin and hematocrit values, defining normal as within 2 standard deviations of the mean or encompassing 95% of the observed variation. Male hematocrit averaged 52.7% and hemoglobin averaged 17.3 m/dL whole blood. The corresponding female values were 48.3% and 15.8 g/dL whole blood, respectively. The range of normal values was 45% to 61% for hematocrit and 13 to 21 g/dL for hemoglobin in the men and 41% to 56% for hematocrit and 12 to 19 g/dL for hemoglobin in the women. These data indicate that hematocrit values above 61% in men or 56% in women and hemoglobin values above 21 g/dL whole blood in men or 19 g/dL whole blood in women are outside the normal range.