Evaluation of Different Methods of Haemoglobin Estimation Among Malaria-Infected Patients

Haemoglobin (Hb) estimation is essential for assessing anaemia, particularly in malaria-endemic settings. Automated Full Blood Count (FBC) analysers, cyanmethemoglobin spectrophotometry, and portable Hb meters are commonly used, but differences in analytical performance may affect measurements.

This cross-sectional study compared Hb measurements obtained using an automated FBC analyser, the cyanmethemoglobin method, and a portable Hb meter among 100 malaria-infected patients aged 16-65 years at Kumasi South Hospital, Ghana. Measurements were compared using Pearson's correlation coefficient, intraclass correlation coefficient (ICC), Lin's concordance correlation coefficient (CCC), Bland-Altman analysis, percentage error, and Passing-Bablok regression.

The three methods showed very strong correlations (r = 0.955-0.992, p < 0.001), excellent ICC (single measures = 0.969; average measures = 0.990), and high concordance (CCC = 0.95-0.99). Mean biases were -0.06 g/dL for FBC analyser versus portable Hb meter, -0.25 g/dL for FBC analyser versus cyanmethemoglobin, and -0.20 g/dL for portable Hb meter versus cyanmethemoglobin. The corresponding 95% limits of agreement were -0.59 to 0.47, -1.48 to 0.98, and -1.35 to 0.95 g/dL, respectively. Passing-Bablok slopes were 1.00 for all comparisons. The FBC analyser and portable Hb meter showed the closest agreement.

The three methods demonstrated good agreement and broadly comparable Hb measurements. The findings support the practical use of portable Hb meters where point-of-care testing is required, while recognising that agreement does not establish diagnostic accuracy or analytical validation.