Diagnostic tests for Schistosomiasis for low prevalence settings: a systematic review and Meta-Analysis

BackgroundTests for diagnosing schistosomiasis in areas where prevalence is low due to control programme of the disease should be suffiently sensitive to detect the residual disease. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use. ObjectivesTo compare sensitivity and specificity of new tests, especially rapid diagnostic tests (RDTs), with regard to a certain reference test. MethodsWe searched the electronic databases Pubmed, EMBASE, the Cochrane Library and LILACS up to February 2021. Furthermore we searched results from the previous meta-analyses. We included studies that used microscopy as the reference standard: for S. haematobium, microscopy of urine prepared by filtration, centrifugation, or sedimentation methods; and for S. mansoni, microscopy of stool by Kato-Katz thick smear. Two review authors independently extracted data, assessed quality of the data using QUADAS-2, and performed meta-analysis where appropriate. Grading of evidence was done with the GRADE methodology by using GradePro. Using the variability of test thresholds, we used a bayesian bivariate random-effects summary receiver operating characteristic model for all eligible tests. We investigated heterogeneity, and carried out sensitivity analyses where possible. Results for sensitivity and specificity are presented as percentages with 95% confidence intervals (CI). ResultsThe review gathered 203 articles stating a diagnostic test for the diagnosis of S. haematobium and S. mansoni out of which 114 entered the analyses. Microscopy of Urine filtration or Kato-Katz smears were used as the reference standard. Compared with Kato-Katz smears, AWE-SEA ELISA (Se=94%; Sp=64%) is comparable to CCA1 (Se=87%; Sp=60%). IgG ELISA (Se=93%; Sp=68%) has also a very good ability to detect true positive as well as CAA cassette (Se=73%; Sp=68%). For S. haematobium, proteinuria (Se=59%; Sp=83%) and haematuria (Se=74%; Sp=87%) reagent strips showed reasonably high specificities with a considerably better sensitivity for the haematuria test. There are interesting promising new diagnostic tests that were tested in field studies. However prevalences of the locations where these studies took place are variable and there are no specific study with a high number of patients in areas with low level of schistosomiasis infection.