Diagnostic Adequacy Gap Analysis

Background: Standard-of-care diagnostic tests for major parasitic and fungal infections systematically underestimate true biological prevalence. Stool microscopy misses the majority of intestinal parasitic infections at low burden; commercial serology assays calibrated on reference populations from one geographic or parasite-strain context produce high false-negative rates when applied to genetically distinct parasite populations in other settings. Methods: Synthesis of published head-to-head comparison studies for seven major parasitic/fungal organisms (Strongyloides stercoralis, Trypanosoma cruzi, Toxoplasma gondii, Schistosoma spp., Giardia duodenalis, Cryptosporidium spp., Entamoeba histolytica). For each organism, the published sensitivity of the standard-of-care test was compared against the best available comparator (antigen detection, lowered serology threshold, molecular test, or composite reference standard). An underdetection factor was derived as 1/standard_sensitivity. Country-specific comparative data were compiled for organisms with the richest comparative literature. Results: Standard-of-care test sensitivity ranged from 4–5% (Strongyloides stercoralis single FECT...