dc.description.abstract |
Malaria accounts for approximately 21% of out-patient visits annually in Kenya.
Prompt and accurate malaria diagnosis is critical to ensure proper treatment. In 2013,
formal malaria microscopy refresher training for microscopists and a pilot qualityassurance (QA) programme for routine malaria diagnostics (microscopy and rapid
diagnostic tests) were independently implemented by the national malaria control
program to improve malaria microscopy diagnosis in malaria low-transmission areas
of Kenya. Malaria microscopy is tedious and is a skill that is learnt over time and
through experience. In malaria low-transmission areas, community malaria
parasitaemia prevalences by microscopy are between 1 and 3% during peak malaria
transmission season. This study was conducted to identify factors associated with
malaria microscopy performance in the same areas. From March to April 2014, a
cross-sectional survey was conducted in 42 public health facilities; 21 were QA-pilot
while another 21were non-QA facilities. In each facility, 18 malaria thick blood slides
archived during January-February 2014 were selected by simple random sampling.
January-February are not peak malaria seasons in Kenya. Each malaria slide was reexamined by two expert microscopists masked (blinded) to health-facility results.
Expert results were used as the reference for microscopy performance measures.
Logistic regression with specific random effects modelling was performed to identify
factors associated with accurate diagnosis of malaria through microscopy technique.
Of the 756 malaria slides collected, 204 (27%) were read as positive by health-facility
microscopists and 103 (14%) as positive by experts. Overall, 93% of slide results from
QA-pilot facilities were concordant with expert reference compared to 77% in nonQA pilot facilities (p <0.001). Recently trained microscopists in QA-pilot facilities
performed better on microscopy performance measures with 97% sensitivity and
100% specificity compared to those in non-QA pilot facilities (69% sensitivity; 93%
specificity; p <0.01). The overall inter-reader agreement between QA-pilot facilities
and experts was κ=0.80 (95% CI: 0.74-0.88) compared to κ=0.35 (95% CI: 0.24-0.46)
between non-QA pilot facilities and experts (p <0.001). In adjusted multivariable
logistic regression analysis, recent microscopy refresher training (prevalence ratio
[PR]=13.8; 95% CI: 4.6-41.4), ≥5 years of work experience (PR=3.8; 95% CI: 1.5-
9.9), and pilot QA programme participation (PR=4.3; 95% CI: 1.0-11.0) were
significantly associated with accurate malaria diagnosis. Microscopists who had
recently completed refresher training and worked in a QA-pilot facility performed the
best overall. The QA programme and formal microscopy refresher training should be
systematically implemented together to improve parasitological diagnosis of malaria
by microscopy in Kenya. |
en_US |