Quantitative urine culture by reagent strip incubation

The filter paper culture-tetrazolium test ressults have been compared with routine hospital streak plate cultures in 400 random urine specimens. Pseudomonas cultures tended to impart a color change to the test pads which rendered interpretation difficult. While a consistently accurate quantitative interpretation of these cultures did emerge during the course of the trial studies, some degree of observer accommodation and bias, in terms of the manufacturer's instructions and description, was necessary to achieve an appropriate reading. When the hospital laboratory results and culture strip test results are compared in terms of colony counts greater than 10-4 bacteria per milliliter and less than 10-4 bacteria per milliliter, the method was found to be 93% sensitive for the total count and 83% sensitive for the gram-negative count with a specificity correlation of 96% for the total and gram-negative counts, respectively.