Performance of Sahli and colour scale methods in diagnosing anaemia among school children in low prevalence areas

Abstract

SummaryOur aim was to compare the performance of the Sahli and Colour Scale methods in diagnosing anaemia in school children, where the prevalence of anaemia is low and the haemoglobin level ranges from mild to moderate (8-11 g/dl). The study was conducted in February 2001, in Qena Governorate, Upper Egypt. The haemoglobin level measured by the two methods in each child were compared with the result obtained by using a portable haemoglobin photometer ÔHemoCueÕ. A total of 149 school children were included in the study. Using HemoCue, 17.4% children were anaemic; using the Sahli method (SM), 66.4% children were anaemic; and using the Haemoglobin Colour Scale (HCS) method, 57.7% children were anaemic. Neither method detected any cases of severe anaemia (Hb < 7 g/dl). Both the Sahli and Colour Scale methods are sensitive but have low specificity, giving a high rate of false positive results. Both methods perform perform very similarly in haemoglobin measurement; they fulfil many of the criteria for their use at primary health care level and detect almost all cases of anaemia in a given population, even if the level of anaemia is mild. Standards for collection, handling and disposal of blood samples are guaranteed more easily by the HCS than the SM. Moreover, lay people can easily manage the HCS with success after brief training. We suggest to gradually replace the SM by the HCS method in primary health care (PHC) centres. Where anaemia levels are moderate to mild, the use of SM and HCS as tools to define anaemia prevalence might be limited, as they often label healthy individuals as anaemic. Both methods remain a useful diagnostic tool to confirm the diagnosis of clinically suspected anaemia in areas where the prevalence of anaemia is low and the haemoglobin level ranges from mild to moderate.keywords haemoglobin measurement, Haemoglobin Colour Scale method, Sahli method, Egypt

Gender-Specific Protective Effect of Hemoglobin on Arsenic-Induced Skin Lesions

“…It is highly sensitive but not very specific compared with more sophisticated methods for determining anemia such as HemoCue (24). Thus, whereas our estimate of anemia prevalence may be overestimated due to a high number of false positives, it is not likely to be exposure dependent.…”

“…During the baseline clinic visit for both studies, Hb values were measured using Sahli's method (24), a visual acid hematin method that can be easily and economically implemented in the field. This measure was chosen to provide participants with immediate results about their anemia status.…”

Validation of the WHO Hemoglobin Color Scale Method

“…High number of false positives is another problem associated with the WHO color scale. Barduagni et al have reported very low positive predictive value (PPV) for the color scale (26.7%) in a study which assessed the prevalence of anemia among school children in Northern Egypt suggesting that high number of healthy individuals can be labeled as anemic [8]. Similar results were reported by van den Broek et al in a study assessing the potential of WHO color scale in anemia screening of pregnant mothers.…”

749 Validity and reliability of haemoglobin colour scale and its comparison with clinical signs in diagnosing anaemia in pregnancy in Ahmedabad, India

“…Other studies also reported HCS with sensitivities above 80% [14][15][16]. However, Anand et al found a sensitivity of 30% and specificity of 100% for HCS when compared with an autoanalyser [6].…”