Microscopy and outpatient malaria case management among older children and adults in Kenya

Abstract

Summaryobjective To evaluate the accuracy of routine malaria microscopy, and appropriate use and interpretation of malaria slides under operational conditions in Kenya.methods Cross-sectional survey, using a range of quality of care assessment tools, at government facilities with malaria microscopy in two Kenyan districts of different intensity of malaria transmission. All patients older than 5 years presenting to outpatient departments were enrolled. Two expert microscopists assessed the accuracy of the routine malaria slide results.results We analysed 359 consultations performed by 31 clinicians at 17 facilities. Clinical assessment was suboptimal. Blood slide microscopy was performed for 72.7% of patients, who represented 78.5% of febrile patients and 51.3% of afebrile patients. About 95.5% of patients with a positive malaria microscopy result and 79.3% of patients with a negative result received antimalarial treatment. Sulphadoxine-pyremethamine monotherapy was more commonly prescribed for patients with a negative test result (60.7%) than for patients with a positive result (32.4%). Conversely, amodiaquine or quinine were prescribed for only 14.7% of patients with a negative malaria microscopy result compared to 57.7% of patients with a positive result. The prevalence of confirmed malaria was low in both high (10.0%) and low-(16.3%) transmission settings. Combining data from both settings, the sensitivity of routine microscopy was 68.6%; its specificity, 61.5%; its positive predictive value, 21.6% and its negative predictive value, 92.7%.conclusions The potential benefits of microscopy are currently not realised because of the poor quality of routine testing and irrational clinical practices. Ambiguous clinical guidelines permitting treatment of older children and adults with a negative blood slide also undermine rational use of antimalarial drugs.

High Sensitivity and Specificity of Clinical Microscopy in Rural Health Facilities in Western Kenya Under an External Quality Assurance Program

“…12 For example, in Tanzania and Kenya, sensitivity of 70% and specificity of 47-61% of clinical microscopy compared with expert readings has been observed. 13,14 Similar to our results, Kiggundu and others 15 reported sensitivity and specificity 95% following a brief refresher training program. However, their evaluation only included slides prepared 1 month after training.…”

Factoring Quality Laboratory Diagnosis into the Malaria Control Agenda for Sub-Saharan Africa

“…20,21 This finding has led to several attempts at retraining technicians to improve proficiency in malaria diagnosis. Refresher, in-service training of technicians needs to continue where appropriate for short-term needs.…”

Low reliability of home-based diagnosis of malaria in a rural community in western Kenya

“…For example, Giemsa stain microscopy in selected district health laboratories in Kenya had a low sensitivity and specificity -69% and 62% respectively [14]. Other studies elsewhere have shown that Giemsa stain is more sensitive than field stain A and B, with suboptimal performance being attributed to the high workload and poor supervision of laboratory technicians [15].…”

“…On the other hand, the potential benefits of malaria microscopy are currently not realized because of the poor quality of routine testing [6,14]. For example, Giemsa stain microscopy in selected district health laboratories in Kenya had a low sensitivity and specificity -69% and 62% respectively [14].…”