細菌尿診断における亜硝酸試験の検討

Abstract

A nitrite test for bacteriuria was compared with routine microscopic examination in 1, 318 clinical urine specimens and with bacterial culture in 132. Sensitivity, specificity, positive predictive value and accuracy rate are as follows; for diagnosis of bacteriuria more than 10(4) CFU/ml, 53.4%, 88.6%, 90.4 and 65.2%, respectively; for more than 10(5) CFU/ml, 55.4%, 87.8%, 88.4% and 67.2%, respectively. The positive rate for the nitrite test was 21.4% for bacteriuria of > or = 10(4) CFU/ml in gram positive cocci and 56.9% in gram negative rods. False negative results were obtained from gram positive cocci without nitrate reductive activity or from patients with acute uncomplicated cystitis because of insufficient incubation time in urinary tract. However, this simple test is valuable in the detection of bacteriuria in clinical practice with high specificity.