Use of urinary gram stain for detection of urinary tract infection in women
Other
A side centrifuge gram stain was used to screen for bacteriuria in women. For standard culture for slide centrifuges gram staining, 4161 urine specimens were presented in urine preservative tubes. After carefully mixing each urine sample, 0.2 ml was pipette-filled into a slide centrifuge chamber and spun for 5 minutes at 2,000 pm. The slides were heat-fixed, gram stained, and analyzed by laboratory technicians who scanned 12 different oil-immersion zones in a preset pattern. The presence of the same organism in six or more areas was classified as a positive urine screen (E.coli isolated in 75 percent of the females studied). A 0.001ml loop was used to culture urine samples, and the growth of the cultures was compared to slide centrifuge screening. The screen showed a sensitivity of 98 percent, specificity of 90 percent, a negative predictive value of 99 percent, and a positive predictive value of 65 percent when a colony count of 100,000 or more CFU/ml was employed as a reference. The screen demonstrated an 88 percent sensitivity rate, a 95 percent specificity rate, and a negative predictive value when a lower colony count of 10,000 or more CFU/ml was employed as a reference.