Meta-analysis of Urine Heme Dipstick Diagnosis of Schistosoma haematobium Infection, Including Low-Prevalence and Previously-Treated Populations

Background: Urogenital schistosomiasis remains highly endemic in Africa. Current control is based on drug administration, targeted either to school-age children or to high-risk communities at-large. Urine dipsticks for detection of microhematuria offer an inexpensive means for estimating infection prevalence. However, their diagnostic performance has not been systematically evaluated after community treatment, or in areas with continuing low prevalence. The objective of the present study was to perform meta-analysis of dipstick accuracy for S. haematobium infection in endemic regions, with special attention to performance where infection intensity or prevalence was low. Methodology/Principal Findings: This review was registered at inception with PROSPERO (CRD42012002165). Included studies were identified by computerized search of online databases and hand search of bibliographies and existing study archives. Eligible studies included published or unpublished population surveys irrespective of date, location, or language that compared dipstick diagnosis of S. haematobium infection to standard egg-count parasitology. For 95 included surveys, variation in dipstick sensitivity and specificity were evaluated according to study size, age- and sex-specific participation, region, local prevalence, treatment status, and other factors potentially affecting test performance. Independent of prevalence, accuracy was greater in surveys of school-age children (vs. adults), whereas performance was less good in North Africa, as compared to other regions. By hierarchical ROC analysis, overall dipstick sensitivity and specificity for detection of egg-positive urine were estimated at 81% and 89%, respectively. Sensitivity was lower among treated populations (72%) and in population subgroups having lower intensity infection (65%). When the insensitivity of egg count testing was considered (and diagnosis inferred instead from combined hematuria and egg-count findings), overall dipstick sensitivity/specificity were 82%/97%, with significantly better sensitivity (92%) in high prevalence settings. Conclusions/Significance: This analysis suggests that dipsticks will continue to serve as very useful adjuncts for monitoring community prevalence following implementation of population-based control of urogenital schistosomiasis. Author Summary: Schistosomiasis is a chronic human disease caused by infection with multicellular trematode parasites of Schistosoma species. In particular, Schistosoma haematobium colonizes the veins in the pelvis, in and around the urinary tract, and causes inflammation that leads to ulceration and bleeding into the urine. One low-tech, inexpensive means of quickly identifying blood in the urine (hematuria) is to use a chemical reagent strip (dipstick) to test a patient's urine. While many studies have confirmed the usefulness of dipstick-detected hematuria as a proxy for infection in diagnosing infected people before treatment is given, their diagnostic performance after treatment has been uncertain. The current study systematically reviewed 95 available reports of dipstick performance in S. haematobium-endemic areas of Africa and determined, based on a meta-analysis of the primary data, that dipsticks appear to retain their diagnostic accuracy in low prevalence areas and after one or more rounds of treatment. This suggests that dipsticks will continue to be very useful tools in tracking and targeting regional requirements for treatment and prevention of S. haematobium infection as current school- and community-based programs go forward.