Revisión sistemática de la validez de los urocultivos recogidos con bolsa estéril perineal / Systematic review of the validity of urine cultures collected by sterile perineal bags

INTRODUCCIÓN: La bolsa adhesiva perineal es el método más usado en nuestro medio para la recogida de orina para cultivo en el lactante, a pesar de que presenta un alto riesgo de contaminación y de resultados falsos positivos. Nos proponemos cuantificar ambos riesgos a través de una revisión sistemática. MÉTODOS: Búsqueda actualizada a mayo del 2014 en PUBMED, SCOPUS (incluye EMBASE), IBECS; CINHAL, LILACS Y CUIDEN, sin límites de idioma ni tiempo. Se extrajeron porcentajes de orinas contaminadas, falsos positivos, sensibilidad y especificidad (respecto cateterismo o punción vesical). RESULTADOS: Se seleccionaron 21 artículos de calidad media (7.659 muestras). El porcentaje agrupado de orinas contaminadas fue del 46,6% (15 estudios; 6.856 muestras; intervalo de confianza del 95% [IC del 95%], 35,6 a 57,8%; I2: 97,3%). El porcentaje agrupado de falsos positivos fue del 61,1% (12 estudios; 575 muestras; IC del 95%, 37,9 a 82,2%; I2: 96,2%). En 5 estudios se pudieron estimar la sensibilidad (88%; IC del 95%, 81 a 93%; I2: 55,2%) y especificidad (82%; IC del 95%, 75 a 89%; I2: 41,3%), aunque en los recuentos no se incluyeron orinas contaminadas. CONCLUSIÓN: La bolsa adhesiva perineal no es un método suficientemente válido para cultivo de orina porque casi la mitad resultarán contaminados y de los positivos 2 de cada 3 serán falsos. Aun siendo estimaciones imprecisas, por su gran heterogeneidad, deben ser tenidas en cuenta en la elección del método de recogida de orina. Las estimaciones de sensibilidad y especificidad no son aplicables por no considerar el riesgo de contaminación

INTRODUCTION: The perineal adhesive bag is the most used method in our country for urine culture collection in infants, despite having a high risk of contamination and false-positive results. We aim to quantify both types of risks through a systematic review. METHODS: Search updated in May 2014 in PUBMED, SCOPUS (includes EMBASE), IBECS; CINAHL, LILACS AND CUIDEN, without language or time limits. Percentages of contaminated urines, false positives, sensitivity and specificity (with respect to catheterization or bladder puncture) were recorded. RESULTS: A total of 21 studies of medium quality (7,659 samples) were selected. The pooled percentage of contaminated urines was 46.6% (15 studies; 6856 samples; 95% confidence interval [95% CI]: 35.6 to 57.8%; I2: 97.3%). The pooled percentage of false positives was 61.1% (12 studies; 575 samples; 95% CI: 37.9 to 82.2%; I2: 96.2%). Sensitivity (88%; 95% CI: 81-93%; I2: 55.2%), and specificity (82%; 95% CI: 75-89%; I2: 41.3%) were estimated in five studies, but without including contaminated urines. CONCLUSION: The perineal adhesive bag is not a valid enough method for urine culture collection, because almost half are contaminated and, if they are positive, two out of three are false. Although these estimates are imprecise, because of their great heterogeneity, they should be considered when choosing the method of urine collection. The estimates of sensitivity and specificity are not applicable because they do not take into account the risk of contamination

[Systematic review of the validity of urine cultures collected by sterile perineal bags]. / Revisión sistemática de la validez de los urocultivos recogidos con bolsa estéril perineal.

INTRODUCTION: The perineal adhesive bag is the most used method in our country for urine culture collection in infants, despite having a high risk of contamination and false-positive results. We aim to quantify both types of risks through a systematic review. METHODS: Search updated in May 2014 in PUBMED, SCOPUS (includes EMBASE), IBECS; CINAHL, LILACS AND CUIDEN, without language or time limits. Percentages of contaminated urines, false positives, sensitivity and specificity (with respect to catheterization or bladder puncture) were recorded. RESULTS: A total of 21 studies of medium quality (7,659 samples) were selected. The pooled percentage of contaminated urines was 46.6% (15 studies; 6856 samples; 95% confidence interval [95% CI]: 35.6 to 57.8%; I(2): 97.3%). The pooled percentage of false positives was 61.1% (12 studies; 575 samples; 95% CI: 37.9 to 82.2%; I(2): 96.2%). Sensitivity (88%; 95% CI: 81-93%; I(2): 55.2%), and specificity (82%; 95% CI: 75-89%; I(2): 41.3%) were estimated in five studies, but without including contaminated urines. CONCLUSION: The perineal adhesive bag is not a valid enough method for urine culture collection, because almost half are contaminated and, if they are positive, two out of three are false. Although these estimates are imprecise, because of their great heterogeneity, they should be considered when choosing the method of urine collection. The estimates of sensitivity and specificity are not applicable because they do not take into account the risk of contamination.