Article
Reliability of point-of-care circulating cathodic antigen assay for diagnosing schistosomiasis mansoni in urine samples from an endemic area of Brazil after one year of storage at -20 degrees Celsius
Registro en:
FAVRE, Tereza Cristina et al. Reliability of point-of-care circulating cathodic antigen assay for diagnosing schistosomiasis mansoni in urine samples from an endemic area of Brazil after one year of storage at -20 degrees Celsius. Revista da Sociedade Brasileira de Medicina Tropical, v. 55, e0389-2021, p. 1 - 7, 2022.
1678-9849
10.1590/0037-8682-0389-2021
Autor
Favre, Tereza Cristina
Beck, Lilian Christina Nóbrega Holsback
Bezerra, Fernando Schemelzer Moraes
Graeff-Teixeira, Carlos
Coelho, Paulo Marcos Zech
Enk, Martin Johannes
Katz, Naftale
Oliveira, Ricardo Riccio
Reis, Mitermayer Galvão dos
Pieri, Otávio Sarmento
Resumen
Background: The World Health Organization recommends reliable point-of-care (POC) diagnostic testing to eliminate schistosomiasis.
Lateral flow immunoassay that detects schistosome circulating cathodic antigen (CCA) in urine to establish prevalence thresholds for
intervention in endemic areas is recommended. Stored urine may be useful if surveying at-risk populations is delayed or interrupted by
unforeseen circumstances, such as the current COVID-19 pandemic. This study evaluated the manufacturer’s claim that Schistosoma mansoni
infection can be reliably diagnosed in urine samples stored at -20°C for one year.
Methods: Two-hundred-forty-two subjects from an endemic site in Brazil provided one urine sample each for testing with URINE CCA
(SCHISTO) ECO TESTE® (POC-ECO) and one stool sample each for testing with Kato-Katz (KK) and Helmintex® (HTX) as a robust reference
standard for infection status. At least 2 ml of urine from each participant was stored at -20°C; after one year, 76 samples were randomly
selected for POC-ECO retesting.
Results: The POC-ECO agreement between freshly collected and stored urine was inadequate considering trace results as positive
(Cohen’s kappa coefficient κ = 0.08) and negative (κ = 0.36). POC-ECO accuracy was not significantly greater than that of routine KK (54%;
95% confidence interval: 42.1%-65.5%).
Conclusions: The precision and accuracy of POC-ECO have to be optimized in both freshly collected and stored urine before it can be
recommended for use in control programs in Brazil.