Positive tests are all alike, every negative test is negative in its own way: lack of confidence in negative malaria rapid diagnostic tests in the Democratic Republic of the Congo.

Malaria overdiagnosis contributes to misuse of antimalarials and mistreatment of other illnesses. Although the DRC's national guidelines mandate rapid diagnostic tests (RDTs) for malaria testing and treatment, healthcare providers overreport malaria cases compared to the proportion of positive tests interpreted and recorded by an automated Deki reader and uploaded to a cloud server. Significantly higher test positivity rates (TPRs) are reported through the national Health Management Information System (HMIS) compared to the Deki reader database, especially in the dry season. Understanding the reasons behind malaria overdiagnosis and overreporting is important for providing appropriate treatment and avoiding antimalarial over-prescription. This qualitative study explores factors influencing provider nonadherence to malaria RDT results. Sixty-four semi-structured interviews were conducted with staff at 16 primary-level health facilities in Kasai Central and Haut Katanga provinces. Twelve key informant interviews with health officials and 24 focus groups with community members provided additional context. Providers and health facility supervisors were less likely to trust RDT results when they were negative than positive. To many providers, fever was synonymous with malaria and a positive RDT provided confirmation of their presumptive diagnosis while a negative RDT challenged it. To integrate the negative RDT into their existing mental model, providers explained how RDTs could return false negative results. Explanations for why RDTs may be inaccurate included that improperly treated malaria can result in a negative test, RDTs are negative early in infection, RDTs do not capture all malaria species, and the wide range in RDT accuracy. Providers and technical personnel noted financial incentives to carrying out microscopic examination rather than RDTs as per DRC's national guidelines. Guidance communicated to service providers in high-endemic, low-resource malaria settings prior to RDT availability, such as presumptive treatment of all fevers as malaria, leads providers to oppose basing treatment decisions on RDT results. Sharing data on RDT efficacy at the country level could increase confidence in RDT results, and better understanding of how RDTs work and what they measure would dispel misconceptions about false negatives. Better oversight of facility-level data, and comparisons with neighboring facilities, could improve adherence to national guidelines in the DRC.