Accuracy of Griess Test to Predict Asymptomatic Bacteriuria during Pregnancy

Abstract

Background: Screening of asymptomatic bacteriuria (ASB) is strongly recommended to detect and treat as preventive health services for safe outcome of pregnancy. Untreated ASB is a potential risk factor for mother and baby. Culture is the gold standard method to detect ASB but cannot be adopted everywhere in our province as it is available in few major cities. The objective of this study was to see the accuracy of Griess test as a screening test to detect nitrates reducing bacteria in urine.

Method: In this study the pregnant women coming for antenatal check up and registration in the Gynae/Obs Department of JPMC were included according to prescribed criteria during the period of September 2001, to March 2002. Urine was collected as midstream voided specimen and immediately transported to the laboratory, where the specimens were processed for Griess test and culture. The results were recorded and calculated for sensitivity and specificity of the test.

Results: The specimen of 290 cases were examined for bacteriuria with Griess test and also inoculated on media. There were 18 cases positive for bacteriuria with Griess test. Culture positive 24 cases were found. The culture positive 6 cases were found mixed growth (contaminants) and rest of the growth were pure growth giving 75% sensitivity and 97.79% specificity of the test.

Conclusion: Although Griess test cannot be compensatory for culture it can be applied as a screening test due to good sensitivity and specificity. It is easy to perform with instant results and to interpret with out going special training for it.