Comparison of haemoglobin concentration measurements using HemoCue-301 and Sysmex XN-Series 1500: A survey among anaemic Gambian infants aged 6-12 months.

Abstract

Background: In low-income countries, point-of-care photometers are used in the screening and management of anaemia in individuals, but also in the assessment of population iron status when evaluating efficacy of intervention studies or public health interventions.

Aims: We aimed to evaluate the accuracy of a commonly used photometer, HemoCue-301, in determining haemoglobin concentration among anaemic children aged 6-12 months in a field setting in rural Africa.

Methods: This report concerns a secondary analysis of data from Gambian infants being screened for an ongoing randomized controlled trial. In those found to be anaemic by HemoCue-301, haemoglobin concentration was measured by Sysmex XN-1500, an automated haematology analyser that was used as a reference. Passing-Bablok regression analysis was used to estimate the regression constant (systematic deviation between two measurement methods that remain consistent across the range of measurements) and proportional bias (systematic deviation between two measurement methods that change in magnitude relative to the value being measured).

Results: Analysis was based on 227 participants. There was strong evidence of absolute bias among moderately anaemic participants (haemoglobin concentration at 8.0g/dL) (absolute bias: 1.12g/dL; 95% CI: 0.91 to 1.37g/dL; proportional bias: 14.0%; 95% CI: 11.4% to 17.1%) in haemoglobin concentrations measured by HemoCue-301 compared to those measured by Sysmex XN-Series1500. Bias was marginal at haemoglobin concentration of 11.0g/dL (absolute bias: -0.08g/dL; 95% CI: -0.18 to 0.07g/dL; proportional bias: -7.3%; 95% CI: -6.5% to 0.6%).

Conclusion: Haemoglobin measurements by HemoCue-301 seem substantially biased in participants with haemoglobin less than 8.0g/dL.