Differences between observed and estimated by hematocrit hemoglobin and its relevance in the diagnosis of anemia among coastal population in Venezuela: Analysis of the second national study of human growth and development (SENACREDH)

Objectives. To evaluate the differences between the observed hemoglobin levels and those estimated based on hematocrit in the context of the 2^nd National Study of Human Growth and Development of the Venezuelan Population (SENACREDH). Materials and methods. 6,004 individuals were chosen by a probabilistic multistage cluster sampling representing 7,286,781 inhabitants from North Central Coastal area (Vargas, Carabobo, Capital District, Aragua and Miranda). Means of observed and estimated hemoglobin (hematocrit/3) were compared, using t test for related samples and linear regression. Results. Mean difference between the values of observed and estimated hemoglobin was -0.3446 ±0.0002 (p<0.001); signifcantly overestimating the hemoglobin values. Regression models of hemoglobin on hematocrit showed an r²=0,87. In order to correct the estimation, we propose a new formula for calculating hemoglobin based on haematocrit values: estimated hemoglobin=(Haematocrit/3.135)+ 0.257. Conclusions: There is an overestimation of hemoglobin levels from hematocrit levels and therefore an underestimation of the prevalence of anemia; however, a high positive correlation between them was found, allowing modeling for achieving a better estimation of the hemoglobin from the hematocrit value.