Diagnostic accuracy of rapid tests for sexually transmitted infections in symptomatic women.

OBJECTIVE: To determine the diagnostic accuracy of tests developed for use at the point of care for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and syphilis in women having symptoms of lower urinary tract infection. METHODS: Cross-sectional study involving sexually active 14-49-year-old women with lower urinary tract infection symptoms consulting during 2010 at a private health clinic and at two public hospitals in Bogotá, Colombia. Pregnant women, those with a previous hysterectomy or those who received antibiotics during the previous 7 days were excluded. Sequential sampling was used; sample size: 1500 women. The ACON NG and CT duo test combo and the ACON individual test plates for NG and separately for CT were used. The QuickVue Chlamydia rapid test (RT) was also used. All of them were compared with nucleic acid amplification methods. The SD Bioline 3.0 and ACON test for syphilis were evaluated and compared with serological tests. Sensitivity and specificity were estimated. RESULTS: CT RTs had a sensitivity that ranged between 22.7% and 37.7% and specificity between 99.3% and 100%. Sensitivity for NG with ACON Duo was 12.5% and specificity 99.8%. Tests for syphilis had a sensitivity of 91.6-100% and a specificity of 99.7-97.8%. CONCLUSIONS: The RTs studied are not useful for screening for NG at the point of care. In case of CT a recommendation about their use in routine care should be supported by a cost-effectiveness analysis. In screening populations at high risk of sexually transmitted infections or pregnant women, the RTs for syphilis should be used.

Prevalencia y factores asociados a la infección por C. trachomatis, N. gonorrheae, t. vaginalis, C. albicans, sífilis, VIH y vaginosis bacteriana en mujeres con síntomas de infección vaginal en tres sitios de atención de Bogotá, Colombia, 2010 / The prevalence of and factors associated with C. trachomatis, N. gonorrheae, t. vaginalis, C. albicans infection, syphilis, Hiv and bacterial vaginosis in females suffering lower genital tract infection symptoms in three healthcare attention sites in bogotá, colombia, 2010

Objetivo: estimar la prevalencia y etiología de las infecciones de transmisión sexual, y de las infecciones endógenas en mujeres en edad reproductiva con síntomas de infección del tracto genital inferior sintomáticas, y describir los factores asociados.Materiales y métodos: estudio de corte transversal en tres centros de atención en Bogotá. Se realizó el diagnóstico etiológico mediante puntaje de Nugent para vaginosis bacteriana (VB), cultivo para Candida, y frotis en fresco para trichomonas. En un subgrupo de pacientes se realizó cultivo In Pouch TM para T. vaginalis (TV), PCR para C. trachomatis (CT) y N. gonorroheae (NG), y pruebas serológicas para sífilis y VIH. Los factores de riesgo fueron evaluados comparando los dos grupos por medio del Odds Ratio (OR) y el intervalo de confianza del 95 por ciento. Resultados: 1385 mujeres fueron incluidas, de ellas 115 (8,3 por ciento) eran trabajadoras sexuales. Se confirmó la presencia de alguna infección del tracto genital (ITG) en 731 (52,7 por ciento) de las mujeres; 560 (40,4 por ciento) presentaron infecciones endógenas y 170 (12,3 por ciento) infecciones de transmisión sexual (ITS). La etiología más frecuente fue la VB en 549 (39,6 por ciento), seguida por candidiasis en 153 (11 por ciento). CT fue detectada en 134 (9,7 por ciento y NG en 19 (1,4 por ciento). TV fue detectada por frotis en fresco en 11 (0,8 por ciento) y por cultivo en 8 de 634 (1,2 por ciento), sífilis en 12 (0,8 por ciento) y VIH en 1 (0,07 por ciento). Las mujeres trabajadoras sexuales tuvieron mayor riesgo de presentar cualquier ITS (OR: 2,0; IC 95 por ciento 1,2-3,3). Las mujeres con ITS tuvieron una edad promedio de 27,9 (± 7,8), y aquellas que no tenían ITS de 31,9 (± 8,9) años. El consumo de licor con frecuencia entre diaria y semanal fue mayor en las mujeres con ITS (OR: 2,6; IC 95 por ciento: 1,4-4,5). Conclusiones: se identificó la etiología en el 52,7 por ciento de las mujeres que consultaron por síntomas de infección del tracto genital inferior. La infección más frecuente fue vaginosis bacteriana, y clamidia dentro de la infecciones de transmisión sexual. No se identificó ninguna etiología infecciosa específica en el 47,3 por ciento de las mujeres aun cuando se utilizó el patrón de oro diagnóstico para los diferentes microorganismos.

Objective: Determining the prevalence and aetiology of sexually-transmitted infections and endogenous infections in women of childbearing age having lower genital tract infection symptoms and describing the pertinent risk factors. Materials and methods: This cross-sectional study was carried out at three outpatient healthcare centres in Bogotá, Colombia. Etiologic diagnosis was made using Nugent’s criteria for bacterial vaginosis, blood agar culture for Candida and wet mount for T. vaginalis. The In-pouch culture technique was used for T. vaginalis, the polymerase chain reaction for C. trachomatis and N. gonorroheae and serological tests for syphilis (RPR, TPHA) and HIV on a sample of the afore mentioned population. Results: 1,385 females were recruited in 2010. 115 (8.3 percent) were sex workers. An LGTI was confirmed in 731 (52.7 percent); 560 (40.4 percent) had an endogenous infection and 170 (12.3 percent) a sexually-transmitted infection (STI). The most frequent aetiology were bacterial vaginosis (39.6 percent), candidiasis (11 percent), C. trachomatis (9.7 percent) and N. gonorroheae (1.4 percent); Trichomona was detected by wet mount (0.8 percent) and culture (1.2 percent), as were syphilis (0.8 percent) and HIV (1 case). Sex workers had a higher risk of having an STI (2.0 OR; 1.2-3.3 95 percent CI), as were younger females (28 ± 7.8 cf 32 ± 8.9) (p = 0.001) and alcohol users (2.6 OR; 1.4-4.5 95 percent CI). Conclusions: Aetiology was identified for 52.7 percent of the females who consulted for lower genital tract infection symptoms; bacterial vaginosis was the most common and Chlamydia the most frequent sexually-transmitted infection. No specific aetiology was identified in almost the same number of females (47.3 percent), even when using gold-standard diagnostic technology for each microorganism.

Probabilidad de infección reciente por VIH en pacientes con presencia de antígeno p24 y prueba confirmatoria negativa / Probability of recent HIV infection in patients with presence of p24 antigen and negative confirmation test

Introducción: La inclusión en las pruebas de detección del VIH de la capacidad de determinar el antígeno p24 ha potenciado su capacidad diagnóstica para infecciones recientes. Objetivos: Evaluar el antígeno p24 como predictor de infección reciente por VIH en pacientes con prueba confirmatoria negativa. Método: Estudio descriptivo de seroconversión en 245 muestras de personas desde los 14 años de edad con resultado confirmatorio negativo para el VIH, en muestras de las serotecas de los laboratorios de Salud Pública Distrital y el Centralizado de VIH en la ciudad de Bogotá, Colombia. Se encontraron en 12 de ellas y se estudió la seroconversión en 6. Resultados: Se confirmó seroconversión en el 60% de pacientes positivos para prueba presuntiva de p24 y en el 75% de los positivos para confirmatoria del mismo antígeno. Conclusiones: Estos resultados sugieren la necesidad de realizar pruebas diagnósticas adicionales a todos los casos con resultado reactivo en prueba presuntiva y negativo para confirmatoria, en los que la reactividad de la primera pueda estar determinada por la presencia del antígeno p24 en a muestra, a fin de establecer una posible infección reciente por este virus.

Background: The inclusion of the capacity to generate p24 antigen in presumptive tests to detect the Human Immunodeficiency Virus (HIV) have enhanced its diagnosing potential in recent infection cases. The absence of this condition in confirmatory tests creates a risk of false negatives. Aims: To assess p24 antigen as a predictor of recent HIV infection in patients with negative confirmation test. Methods and design: Descriptive study of seroconversion of patients with confirmed negative test for HIV. Scenario: A study based on samples taken from the erum banks of the District Public Health Lab and Centralized HIV Lab in Bogotá, D.C., Colombia. Participants: p24 antigen was sought in 245 samples of people aged 14 or older, either reactive for presumptive tests or negative for confirmatory tests. The antigen was found in 12 of them and seroconversion took place in 6 of them. Interventions: 253 blood samples, either reactive for presumptive tests or negative for confirmatory tests were obtained out of 393,247 samples taken between January 2006 and November 2007. Finally, seroconversion was studied in patients with reactive test for p24 antigen. Outcome measurement: Seroconversion took place in patients with reactive tests for p24 antigen test for presumptive test and negative confirmatory test. Results: Seroconversion was confirmed in 60% of the patients tested positive for presumptive p24 antigen and in 75% of the patients tested positive for confirmatory test of the same antigen. Conclusions: These results suggest the need to carry out additional diagnostic tests to all cases with reactive results in presumptive testing and negative confirmatory testing in which the reactivity of the presumptive testing can be determined by the presence of p24 antigen in the sample, in order to establish a possible recent infection by this virus.