Comparison of indirect cyanmethaemoglobin method and TrueHb haemometer point of care test with direct cyanmethaemoglobin (gold standard) method for strengthening anaemia detection at primary health care level

Abstract

Introduction: The most reliable indicator for anaemia diagnosis at the population level is haemoglobin (Hb) estimation. The direct cyanmethaemoglobin method is considered the gold standard method for haemoglobin estimation. However, for resource constraint areas like primary health care (PHC) level, either blood samples are transported on filter paper for Hb testing (indirect cyanmethaemoglobin method) in laboratory or point of care testing is commonly used. Therefore, a comparative analysis of haemoglobin estimation of direct with indirect cyanmethaemoglobin method and also with TrueHb (Wrig Nanosystems Pvt. Ltd.) haemometer was done to strengthen anaemia diagnosis at the PHC level. Materials and Methods: This was a cross-sectional study. A total of 90 participants above 9 years of age, who visited the outpatient department (OPD) of health centre, Kheri and gave consent were included. Comparative analysis was done between Hb concentration assessed by indirect cyanmethaemoglobin method and TrueHb haemometer device against the gold standard method. Results: The mean Hb value estimated by direct method, TrueHb haemometer and indirect methods (filter paper A, B and C) was 11.42 ± 1.59 g/dl, 11.52 ± 1.54 g/dl, 10.66 ± 1.52 g/dl, 9.84 ± 1.50 g/dl and 10.19 ± 1.62 g/dl, respectively. There was no significant difference found between the mean Hb concentration estimated by the direct method and the TrueHb haemometer device. However, there was a significant difference in mean Hb values between the direct method and the indirect method. Therefore, regression analysis was done to estimate the correction factor for the indirect method. Conclusion: TrueHb metre device gave promising results in comparison to the gold standard method and can be used if resource permits in PHC centres. Indirect methods of haemoglobin estimation can be an alternative in resource-constraint settings, specifically for surveys. However, further studies are required for the validation of the indirect method.

Keywords

• anaemia
• cyanmethaemoglobin method
• haemoglobin estimation
• point of care test
• truehb haemometer device