Resum
Screening for asymptomatic bacteriuria during pregnancy, the major risk factor for symptomatic urinary tract infection during pregnancy have been recommended.This cross sectional study was conducted to determine prevalence of asymptomatic bacteriuria in Ibadan and evaluate the diagnostic accuracy and relative cost effectiveness of dipstick tests for nitrite and leucocyte esterase in comparison to laboratory culture. Two hundred and five patients, presenting for their first antenatal visit at the University College Hospital, Ibadan, participated in the study. Urine samples obtained from the participants were subjected to two tests; reagent dipstick test for nitrite and leucocyte esterase and routine laboratory culture, which is the gold standard for diagnosis. Main outcome measures were sensitivity, specificity, positive and negative predictive values of the reagent dipstick tests as well as likelihood ratios. The prevalence of asymptomatic bacteriuria in pregnancy with routine laboratory culture and using combined leucocyte esterase and nitrite strip tests were 10.7% and 11.7% respectively. Compared with laboratory culture, combined strip tests had sensitivity, specificity and negative predictive values of 50%, 92.9% and 93.9% respectively, indicating a statistically significant lower level of accuracy (P < 0.05). The corresponding likelihood ratios for positive and negative strip tests (LR+ and LR-) were 7 and 0.5 respectively. The study concludes that combined Leucocyte esterase-nitrite dipstick test is not sufficiently sensitive and specific to be used for routine screening of bacteriuria in pregnancy in place of laboratory culture, though may be more cost effective in low resource settings.
Keywords: Asymptomatic bacteriuria, pregnancy, dipstick tests, laboratory culture
Résumé
Le dépistage de la bactériurie symptomatiques pendant la grossesse, le risqué majeur de l’infection symptomatique de la voie urinaire pendant la grossesse ont été recommandé. Cette étude était conduite dans le but de déterminer le taux de la bactériurie asymptomatique à Ibadan et évaluer le diagnostic juste et le cout effectif relatif des tests rapide par nitrite et estérase leucocyte en comparaison avec la culture au laboratoire. Deux cent cinq patients, se présentant pour leur première visite à la clinique anténatale au centre universitaire hospitalier, Ibadan participaient a cette étude. Les échantillons d’urine étaient obtenues de chaque participant et étaient soumisse a deux tests: le test à kit de nitrite et leucocyte estérase et la culture au laboratoire, qui est le standard pour le diagnostic. Les mesures des résultats étaient la sensitivité, spécificité, les valeurs prédictives positive et négative des tests à kit aussi bien que l’estimation des proportions. La prévalence de la bactériurie asymptomatique en grossesse avec la culture en laboratoire et combinant avec les tests kits de leucocyte estérase et nitrite étaient de 10.7% et 11.7% respectivement. L’étude comparée de la culture et les tests à kits combines avait une sensibilité, une spécificité et des valeurs prédictives négatives de 50%, 92.9% et 93.9% respectivement, indiquant une valeur statistique significativement faible (P < 0.05). Les proportions correspondantes des tests à kit positifs et négatifs (LR+ et LR-) étaient de 7 et 0.5 respectivement. Cette étude a conclut que le combiné test kit de leucocyte estérase- nitrite n’est pas suffisamment sensible et spécifique à être utilisé de façon routinier dans le dépistage de la bactériurie pendant la grossesse que la culture, bien que qu’elle peut être plus coûteux dans les pays sous développés.
Correspondence: D.O Awonuga, Department of Obstetrics and Gynaecology, Federal Medical Centre, Abeokuta. P.M.B. 3031 Sapon Post Office, Abeokuta, Ogun State, Nigeria. E-mail – lekanawonuga@yahoo.com
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