[Screening for bacteriuria in the laboratory: autotrak, test strips and microscopic examination compared with...

A prospective investigation was undertaken to compare quantitative culture of 739 samples of urine in a microbiological laboratory with the screening methods: phase contrast microscopy examination, test strip examinations for nitrite and leukocyte esterase (Multistix-2, Ames) and "Autotrak" (automatic quantitating of the bacterial content in fluids: BBT instruments). The three screening methods were, by and large, of equal value as regards true positive diagnostic frequency (0.48-0.55) and true negative diagnostic frequency (0.92). The methods were also equally rapid but microscopy examination was by far the cheapest (0.15 Danish crowns per test as compared with 1.75 for test strips and 3.10 for "Autotrak"). In addition, microscopic examination has the further advantage, although this of lesser value where cocci are concerned, of being capable of differentiating the morphology of the bacteria and their motility. It is noted that test strips have a false negative rate of approximately 13%.