This implementation has shown a high level of clinicians' acceptance of malaria rapid diagnostic tests and appropriate use of test results to guide clinical management of febrile patients. The overwhelming majority of patients tested with RDTs had a history of fever or presented with fever to the facility, indicating appropriate case selection for RDT testing. Over half of all patients tested with RDTs had a positive result. The percentage of positive RDT results increased as would be expected in the months following the rainy season and then gradually declined.10
Over half of the RDTs were read as positive, and clinician confidence in RDT results remained high. It is unclear if similar confidence in RDT results would be found in an area of lower transmission where a smaller proportion of RDTs would be positive. However, we did not see an increase in the number of RDT-negative patients treated with antimalarials during months where the percentage of positive RDT results was relatively lower.
The study also showed good adherence to the country's malaria treatment policy. In light of increased antimalarial drug resistance, the Tanzanian NMCP changed national malaria treatment policy twice within less than a decade. In late 2001, chloroquine (CQ) was replaced with sulphadoxine-pyrimethamine (SP) as the first-line treatment of uncomplicated malaria, and in 2006, SP was replaced by artemether-lumefantrine. Quinine remains the drug of choice for severe malaria. A very high proportion of confirmed malaria cases in this study received AL and quinine, as did most of the relatively few treated with antimalarials despite a negative test.
Only 2.0% of children < 5 years of age that were seen at health facilities were tested with RDTs and the remainder received presumptive treatment of malaria according to the 2006 national malaria guidelines. An even smaller percentage of adults and children 5 years of age and older were treated for malaria without being tested. This shows that different treatment policies can be successfully implemented for children under 5 (presumptive treatment of febrile illness per IMCI guidelines) and adults and older children based on RDT results. Although previous studies have documented concerns that IMCI presumptive treatment policies might be extended to older age groups,6,8
this study did not document such extension. However, no RDT stockouts were observed during the study period. It is likely that in the absence of a diagnostic test such extension might occur.
The WHO has recently recommended that all patients with suspected malaria should receive confirmatory testing.11
Given the limitations in guaranteeing adequate supplies of other malaria commodities (ACTs, long lasting insecticidal nets [LLINs], etc.) and the frequent stockouts of RDTs observed in areas where RDTs have already been introduced, an implementation strategy that limits diagnostic confirmation of malaria to adults and children 5 years of age and older may be a logical way of rationing available rapid diagnostic tests. Given the variability in RDT performance in the WHO/Foundation for Innovative New Diagnostics (FIND) product testing,12
it may take several years to have sufficient numbers of quality manufacturers of RDTs to meet the global demand necessary to follow universal testing guidelines. Insufficient funding of diagnostics, poor forecasting of needs and distribution of supplies, and inadequate human resource capacity may further limit universal testing initiatives. In the interim, continuation of the IMCI policy of presumptive treatment of children < 5 years of age may be a reasonable alternative until RDT stocks are sufficient to meet demand. However, universal testing of suspected malaria cases before treatment should remain the objective.
Training for this implementation was conducted at each health facility or a nearby school. On-site training made it possible for all staff members and volunteers present on the training day to participate. Because nearly every staff member had received RDT training, all personnel performed RDTs and supervisory visits provided an opportunity to inform and train individuals not present on the original training date. Supervisory visits increased confidence in the diagnostic test and provided an opportunity for feedback on how the tests were performing and being used for clinical decision making. Job aides and training materials were also used extensively by health facility staff.
In this study about 5% of patients tested with RDTs had received antimalarial treatment in the 3 weeks before presentation. Because HRP2 antigens can continue to circulate for up to 56 days (median 32 days) after appropriate antimalarial treatment,13
it is possible that some tested patients were not parasitemic and did not require antimalarial treatment. The message that febrile patients who received antimalarial treatment in the 3 weeks before presentation should be referred to a higher level facility with microscopy must be reinforced during supervisory visits to reduce unnecessary retreatment, detect treatment failures, or identify other causes of fever. Appropriate referral of patients previously treated with antimalarials remains a challenge in rural health facilities.
There are several limitations to this evaluation of RDT use in routine case management. First, there was limited data collected from patients who were not tested for malaria. Therefore, we do not know if the patients who were presumptively treated for malaria had signs of severe disease or other reasons for presumptive malaria treatment (jaundice, hepatosplenomegally, etc.). Furthermore, we did not collect additional data on clinical signs and symptoms other than the presence or absence of fever among patients tested with RDTs. As such, we are unable to evaluate the potential reasons that patients may have received antimalarial treatment with a negative RDT result. We are also unable to assess the correct prescription of antibiotics to patients that tested RDT negative. However, we are encouraged that the majority of RDT-negative patients with alternative treatments recorded were treated with antipyretics or anti-inflammatory drugs. This may indicate that as malaria prevalence decreases in Tanzania clinicians are becoming increasingly comfortable with the differential diagnosis of febrile illness, which includes a high proportion of viral illnesses in all epidemiologic settings.
Implementation of RDTs in rural health facilities resulted in high adherence to national treatment guidelines. Emphasis should be placed on providing clear treatment algorithms, quality control, and supervision. Patients testing negative by RDT were rarely treated with antimalarials. Unapproved antimalarials were seldom used. Quality assurance increased health worker's confidence in RDT performance and remains an essential part of RDT implementation. Health workers continued to follow national guidelines for the empiric treatment of febrile children. Clinicians frequently used antipyretics, anti-inflammatory drugs, and antibiotics to treat RDT-negative patients, which may indicate increasing awareness of the differential diagnosis of febrile illness.