Evaluation of the WHO Haemoglobin Colour Scale for diagnosis of anaemia in children and pregnant women as used by primary health care nurses and community health workers in western Kenya

Abstract

To evaluate the diagnostic accuracy of the WHO Haemoglobin Colour Scale (HCS) for anaemia in three groups of children aged 2 months to 2 years (sick children, those visiting an immunization clinic and a community-based random sample of children) and a sample of pregnant women. Finger-prick blood samples were taken from all consenting participants. Haemoglobin (Hb) levels from the HCS were compared with results from a HemoCue portable haemoglobinometer. Sensitivity, specificity and positive and negative predictive values for the HCS were calculated. A total of 457 sick children, 336 children visiting immunization clinics, 454 children from the community at large and 643 pregnant women participated. The prevalence of anaemia (Hb<11 g/dl) in these groups was 87%, 79%, 74% and 52%, respectively. The prevalence of severe anaemia (Hb<7 g/dl) was 24%, 11%, 10% and 2%, respectively. The sensitivity of the HCS for anaemia ranged from 60% to 79% and specificity from 59% to 94%. The sensitivity of the HCS for severe anaemia ranged from 24% to 63% and the specificity from 97% to 100%. Through use of the HCS, the proportion of sick, anaemic children visiting peripheral health facilities diagnosed and treated for anaemia would increase from 3% to 65%. In an area with high prevalence of anaemia among sick children, use of the HCS has the potential to significantly increase the proportion of sick, anaemic children who are diagnosed with anaemia and given appropriate treatment. Further evaluations of the effect of the use of the HCS on treatment practices at the health facility level are required.