Method-comparison study of a hemoglobinometer and a hematology analyzer to measure hemoglobin concentration among women with genetic hemoglobin disorders in Cambodia

Abstract

Background: Genetic hemoglobin (Hb) E variants are common in Cambodia and result in an altered and unstable Hb molecule. There are no known studies on the accuracy of Hb measurement among individuals with Hb E or other Hb variants. Methods: This method-comparison study evaluates two methods to measure Hb concentration in capillary blood using a hemoglobinometer (HemoCueÒ) and in venous blood using an automated hematology analyzer (Sysmex XT-1800i). We determined the bias and concordance between the two methods among 420 non-pregnant women (18-45 y) in Cambodia using secondary data from a separate trial. Results: Bias and concordance appeared similar between methods among women with no Hb disorders (n=195, bias=2.5, rc=0.68), women with Hb E variants (n=133, bias=2.5, rc=0.78), and women with other Hb variants (n=92, bias=2.7, rc=0.73). Overall, agreement was poor between methods. The overall bias was 2.6 g/L (difference in Hb means between methods), resulting in a difference in anemia prevalence of 11.5% (41% using HemoCueÒ and 29.5% using Sysmex, p<0.001). This changes the WHO anemia severity from a ‘moderate’ to a ‘severe’ public health problem. Based on concordance plots, the HemoCueÒ device appears to underestimate Hb concentrations in capillary blood as compared to Sysmex (venous blood) at lower Hb concentrations, and to overestimate Hb concentrations in capillary blood as compared to Sysmex at higher Hb concentrations. Conclusions: Bias and concordance were similar among all groups, suggesting the two methods of Hb measurement were comparable. We highlight the bias between the two methods to caution field staff, researchers and policy makers in the interpretation of data and the impact that even a small bias between methods can have on anemia prevalence rates.

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Keywords

ANEMIA, HEMOCUE, HEMOGLOBINOMETER, HEMOGLOBIN DISORDERS, BIAS, CAMBODIA, 50 METHOD-COMPARISON, HEMOGLOBIN, WOMEN'S HEALTH, HEALTH SURVEYS

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