Clinical diagnosis of malaria by medical assistants in Sri Aman, Sarawak - necessary but of limited reliability

Rural health clinics in Sri Aman Division in Sarawak, Malaysia lack diagnostic tests for malaria. Many of the medical assistants in the clinic diagnose malaria solely on clinical ground. The study was to determine the sensitivity, specificity and positive predictive value of clinical diagnosis of rnahtria made by medical assistants using results of microscopy examination as gold standard. The study period was from September to December 2003. Three rural clinics without laboratory or diagnostic tests services and one urban clinic with laboratory facility serving malarious areas were selected. All patients clinically diagnosed as malaria by the attending medical assistants were included as clinical malaria cases. Blood slides were taken for examination of malaria parasites. Non clinical malaria cases were all other patients without clinical malaria for whom blood slides were taken for malaria parasites. Out of 362 patients included in the study, 75 were clinically diagnosed as having mahria. The sensitivity of headache, history of fever and chills/rigors to detect malaria cases was above 90% but the specificity and positive predictive value was low, below 40% and 20% respectively. The sensitivity, specificity and positive predictive value of malaria clinical diagnosis made by medical assistants was 82.1 %, 84 .4% and 30.7% respectively. Clinical diagnosis of malaria increases the slide positive rate by four folds. However the sensitivity, specincity and positive predictive value of clinical diagnosis by medical assistant and clinical characteristics was insufficient to enable each of them to be used alone to differentiate true malaria cases from non mahiria cases