Reference range of hematocrit in the elderly with respect to altitude.

The purpose of this paper is to provide a scientific basis for a unified standard of the reference value of old people's hematocrit in China. The reference values of healthy old people's hematocrit have been collected according to the Wintrobe methods; the relationship between the reference values of old people's hematocrit and altitude has been tested in this paper. It has been found that the reference value of old people's hematocrit increases when the altitude gradually increases, and such relationship is quite significant. The method of mathematical univariate regression analysis is used to deduce two regression equations: $\widehat{Y}$[sub 1] =44.1+0.00351x±4.5, $\widehat{Y}$ [sub 2] =39.5+0.00298x±4.1. If the altitude value of a particular area of China is known, the reference value of old people's hematocrit there can be calculated by means of the regression equations. Furthermore, depending on the altitude, China can be divided into three districts: Qingzang District, Central District and Eastern District. [ABSTRACT FROM AUTHOR]