Prevalence of anaemia in patients attending an outpatient clinic in western Rift Valley in Kenya during a low malaria season

OBJECTIVE

To assess the prevalence of anaemia in outpatients attending a rural health clinic in an area of seasonal malaria, during the low transmission season.

METHODS

Haemoglobin estimation and blood slide examination for malaria parasites were performed on 280 consecutive patients attending outpatient curative services at Entasopia Health Centre, Kajiado District, Kenya, between April-May 1996. Anaemia was defined according to World Health Organisation guidelines for age, sex and pregnancy status.

RESULTS

In all groups except adult males, more than half of the patients tested had haemoglobin values below the lower reference limits, suggesting that anaemia is widely present in this population even during the low malaria season. Only 5% of patients were positive for Plasmodium falciparum malaria. Peripheral blood film examination suggested iron deficiency as the major cause of anaemia.

CONCLUSIONS

Further studies to define the underlying causes of anaemia and to develop community strategies to prevent anaemia are required. The association between fever and anaemia and the use of pallor to diagnose anaemia, are discussed.

Comparison of five methods of malaria detection in the outpatient setting

In eastern Africa where 90% of the malaria is due to Plasmodium falciparum, the accuracy of malaria diagnosis at the outpatient level is becoming increasingly important due to problems of drug resistance and use of alternative, costly antimalarial drugs. The quantitative buffy coat (QBC) technique, acridine orange staining with an interference filter system, and the ParaSight-F test have been introduced as alternative methods to conventional microscopy for the diagnosis of malaria. Two hundred thirteen outpatients were tested using these alternative methods and conventional microscopy by five experienced technologists; two were randomly allocated to read the results of each test. Paired results showed the highest level of agreement with the ParaSight-F test (99%), followed by Field stain (92%). The results of the QBC technique showed the least agreement (73%). Using conventional microscopy as the reference standard, the ParaSight-F test had a sensitivity range of 90-92% and a specificity of 99%, staining with acridine orange had a sensitivity range of 77-96% and a specificity range of 81-98% and the QBC technique had a sensitivity range of 88-98% and a specificity range of 58-90%. All microscopic tests showed lower sensitivities (as low as 20% using staining with acridine orange) in detecting low parasitemias (< or = 320/microl) than the ParaSight-F test (70%). Due to the high cost of the ParaSight-F test, Field-stained blood films remain the most appropriate method for diagnosis of P. falciparum in eastern Africa. The ParaSight-F test may be used in situations where no trained microscopists are available, or where malaria is strongly suspected and the results of microscopy are negative.