Reproducibility matters: intra- and inter-sample variation of the point-of-care circulating cathodic antigen test in two Schistosoma mansoni endemic areas in Uganda.
Philos Trans R Soc Lond B Biol Sci
; 378(1887): 20220275, 2023 10 09.
Article
in En
| MEDLINE
| ID: mdl-37598698
ABSTRACT
Over 240 million people are infected with schistosomiasis. Detecting Schistosoma mansoni eggs in stool using Kato-Katz thick smears (Kato-Katzs) is highly specific but lacks sensitivity. The urine-based point-of-care circulating cathodic antigen test (POC-CCA) has higher sensitivity, but issues include specificity, discrepancy between batches and interpretation of trace results. A semi-quantitative G-score and latent class analyses making no assumptions about trace readings have helped address some of these issues. However, intra-sample and inter-sample variation remains unknown for POC-CCAs. We collected 3 days of stool and urine from 349 and 621 participants, from high- and moderate-endemicity areas, respectively. We performed duplicate Kato-Katzs and one POC-CCA per sample. In the high-endemicity community, we also performed three POC-CCA technical replicates on one urine sample per participant. Latent class analysis was performed to estimate the relative contribution of intra- (test technical reproducibility) and inter-sample (day-to-day) variation on sensitivity and specificity. Within-sample variation for Kato-Katzs was higher than between-sample, with the opposite true for POC-CCAs. A POC-CCA G3 threshold most accurately assesses individual infections. However, to reach the WHO target product profile of the required 95% specificity for prevalence and monitoring and evaluation, a threshold of G4 is needed, but at the cost of reducing sensitivity. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases a decade from the London Declaration on NTDs'.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Schistosoma mansoni
/
Point-of-Care Systems
Type of study:
Risk_factors_studies
Limits:
Animals
/
Humans
Country/Region as subject:
Africa
Language:
En
Journal:
Philos Trans R Soc Lond B Biol Sci
Year:
2023
Document type:
Article
Affiliation country:
Reino Unido