Reproducibility of rapid diagnostic tests for Trypanosoma cruzi infection in endemic areas of Colombia / Reproducibilidad de pruebas de diagnóstico rápido de la infección por Trypanosoma cruzi en áreas endémicas de Colombia

Introduction: Chagas disease is a neglected tropical disease of interest to public health because of its social and economic burden. Identifying infected and sick people with Chagas disease constitutes the first step towards achieving World Health Ooganization's goals for 2020. Objective: To evaluate the reproducibility with gold standard of a rapid diagnostic test for detection of antibodies to T. cruzi; and to propose a diagnostic algorithm for Chagas disease under the point-of-care concept in an area with limited access to health care coverage. Material and Methods: A cross-sectional study was performed to detect antibodies to T. cruzi in 151 indigenous volunteers belonging to three ethnic groups of the Sierra Nevada de Santa Marta, Colombia. Rapid tests-PDR SD BIOLINE Chagas Ab were implemented in the field versus confirmation in the laboratory using two standardized serological methods (ELISAs). Results: The results show that 19,2 percent seroreactivity for T. cruzi was found among the entire population screening. The highest rate of human infection with T. cruzi was detected in the Wiwa community. No significant differences between rapid diagnostic test and the standard techniques (ELISAs) were found. Sensitivity, specificity and concordance for RDT were 100 percent (Kappa: 1,0). Conclusions: The Sierra Nevada de Santa Marta continues to be a hyperendemic area for Chagas disease. The area is difficult to access and has low or no primary health care coverage, making the assessed rapid diagnostic test a useful tool for screening programs and defining treatment and control plans, which represents the first approach at establishing a point-of-care testing strategy for endemic countries for Chagas disease(AU)

Introducción: La enfermedad de Chagas es una enfermedad desatendida de interés en salud pública por su carga social y económica. Identificar personas infectadas y enfermas con el mal de Chagas constituye el primer paso para alcanzar los objetivos de la Organización Mundial de la Salud para el 2020. Objetivo: Evaluar la reproducibilidad de una prueba de diagnóstico rápida para la detección de anticuerpos contra T. cruzi; y proponer un algoritmo de diagnóstico para enfermedad de Chagas bajo el concepto de uso de tecnologías en el lugar de atención en áreas de acceso limitados a los servicios de salud. Materiales y métodos: Se realizó un estudio de corte transversal para la detección de anticuerpos para T. cruzi a 151 indígenas voluntarios pertenecientes a tres grupos étnicos de la Sierra Nevada de Santa Marta, Colombia. Se implementó pruebas rápidas-PDR SD BIOLINE Chagas Ab en campo versus la confirmación en el laboratorio mediante dos métodos serológicos estandarizados (ELISAs). Resultados: Se encontró el 19,2 por ciento de seroreactividad para T. cruzi entre toda la población estudiada. La tasa más alta de infección humana por T. cruzi se detectó en la comunidad Wiwa. No hubo diferencias significativas entre la prueba de diagnóstico rápida y las técnicas estandarizadas (ELISAS). La sensibilidad, especificidad y concordancia para la PDR fue del 100 por ciento (Kappa: 1,0). Conclusiones: La Sierra Nevada de Santa Marta continúa siendo un área hiperendémica para la enfermedad de Chagas. Dado que es un área de difícil acceso, con baja o nula cobertura en atención primaria en salud, la prueba de diagnóstico rápida evaluada se convierte en una herramienta útil como prueba de elección para programas de tamización y definir planes de acción de tratamiento y control, y representa el primer acercamiento de uso de tecnologías en el sitio de atención para el diagnóstico rápido en países endémicos para la enfermedad(AU)

Performance Evaluation of the BD SARS-CoV-2 Reagents for the BD MAX System.

Nucleic acid amplification testing (NAAT) for SARS-CoV-2 is the standard approach for confirming COVID-19 cases. This study compared results between two emergency use authorization (EUA) NAATs, with two additional EUA NAATs utilized for discrepant testing. The limits of detection (LOD) for the BD SARS-CoV-2 reagents for the BD MAX system (MAX SARS-CoV-2 assay), the bioMérieux BioFire respiratory panel 2.1 (BioFire SARS-CoV-2 assay), the Roche cobas SARS-CoV-2 assay (cobas SARS-CoV-2 assay), and the Hologic Aptima SARS-CoV-2 assay Panther (Aptima SARS-CoV-2 assay) NAAT systems were determined using a total of 84 contrived nasopharyngeal specimens with 7 target levels for each comparator. The positive and negative percent agreement (PPA and NPA, respectively) of the MAX SARS-CoV-2 assay, compared to the Aptima SARS-CoV-2 assay, was evaluated in a postmarket clinical study utilizing 708 nasopharyngeal specimens collected from suspected COVID-19 cases. Discordant testing was achieved using the cobas and BioFire SARS-CoV-2 NAATs. In this study, the measured LOD for the MAX SARS-CoV-2 assay (251 copies/ml; 95% confidence interval [CI], 186 to 427) was comparable to the cobas SARS-CoV-2 assay (298 copies/ml; 95% CI, 225 to 509) and the BioFire SARS-CoV-2 assay (302 copies/ml; 95% CI, 219 to 565); the Aptima SARS-CoV-2 assay had an LOD of 612 copies/ml (95% CI, 474 to 918). The MAX SARS-CoV-2 assay had a PPA of 100% (95% CI, 97.3% to 100.0%) and an NPA of 96.7% (95% CI, 94.9% to 97.9%) compared to the Aptima SARS-CoV-2 assay. The clinical performance of the MAX SARS-CoV-2 assay agreed with another sensitive EUA assay.

Trichomonas vaginalis Detection in Urogenital Specimens from Symptomatic and Asymptomatic Men and Women by Use of the cobas TV/MG Test.

Trichomonas vaginalis is a prevalent sexually transmitted infection (STI). Diagnosis has historically relied on either microscopic analysis or culture, the latter being the previous gold standard. However, these tests are not readily available for male diagnosis, generally only perform well for symptomatic women, and are not as sensitive as nucleic acid amplification tests (NAATs). Men are largely asymptomatic but carry the organism and transmit to their sexual partners. This multicenter, prospective study evaluated the performance of the cobas T. vaginalis/Mycoplasma genitalium (TV/MG) assay for detection of T. vaginalis DNA compared with patient infection status (PIS) defined by a combination of commercially available NAATs and culture using urogenital specimens. A total of 2,064 subjects (984 men and 1,080 women, 940 [45.5%] symptomatic, 1,124 [54.5%] asymptomatic) were evaluable. In women, sensitivity ranged from 99.4% (95% confidence interval [CI] 96.8 to 99.9%) using vaginal samples to 94.7% (95% CI 90.2 to 97.2%) in PreservCyt samples. Specificity ranged from 98.9 to 96.8% (95% CI 95.4 to 97.8%). In men, the cobas TV/MG assay was 100% sensitive for the detection of T. vaginalis in both male urine samples and meatal swabs, with specificity of 98.4% in urine samples and 92.5% in meatal swabs. The cobas TV/MG is a suitable diagnostic test for the detection of T. vaginalis, which could support public health efforts toward infection control and complement existing STI programs.

Mycoplasma genitalium Detection in Urogenital Specimens from Symptomatic and Asymptomatic Men and Women by Use of the cobas TV/MG Test.

Mycoplasma genitalium (MG) infections are a growing concern within the field of sexually transmitted infections. However, diagnostic assays for M. genitalium have been limited in the United States. As most infections are asymptomatic, individuals can unknowingly pass the infection on, and the prevalence is likely to be underestimated. Diagnosis of M. genitalium infection is recommended using a nucleic acid test. This multicenter study assessed the performance of the cobas Trichomonas vaginalis (TV)/MG assay (cobas) for the detection of M. genitalium, using 22,150 urogenital specimens from both symptomatic and asymptomatic men and women collected at geographically diverse sites across the United States. The performance was compared to a reference standard of three laboratory-developed tests (LDTs). The specificity of the cobas assay for M. genitalium ranged from 96.0% to 99.8% across symptomatic and asymptomatic men and women. The sensitivities in female vaginal swabs and urine samples were 96.6% (95% confidence interval [CI], 88.5 to 99.1%) and 86.4% (95% CI, 75.5 to 93.0%), respectively. The sensitivities in male urine and meatal swab samples were 100% (95% CI, 94.0 to 100%) and 85.0% (95% CI, 73.9 to 91.9%), respectively. This study demonstrated that the cobas assay was highly sensitive and specific in all relevant clinical samples for the detection of M. genitalium.