title: Evaluation of the cytocentrifuge Gram stain as a screening test for bacteriuria in specimens from specific patient populations.
abstract: To assess the usefulness of the cytocentrifuge Gram stain as a urine screening test in the clinical microbiology laboratory for the elimination of culture for screen-negative specimens, we compared the results of the cytocentrifuge Gram stain to the results of culture for 1,171 urine specimens. The data were analyzed separately for specimens from males (inpatients) and females (inpatients and outpatients), as well as for catheterized and voided specimens. Overall, the cytocentrifuge Gram stain had excellent negative predictive value (97.7%) and sensitivity (92.3%) at a culture threshold of 10(5) colony-forming units per milliliter or more. The negative predictive value and sensitivity decreased at lower culture thresholds in all populations. The negative predictive value decreased most markedly for female outpatients. Because of low positive predictive value and specificity, this test is not reliable as a sole indicator for presumptive therapy in many cases with positive results. If its limitations are recognized, the cytocentrifuge Gram stain is a useful screening test for the rapid exclusion of bacteriuria.
authors.affiliation: Department of Pathology, Northwestern University Medical School, Northwestern Memorial Hospital, Chicago, Illinois 60611, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Winquist
authors.forename: M A
authors.initials: MA
authors.lastname: Orrico
authors.forename: L R
authors.initials: LR
authors.lastname: Peterson
mesh_terms: D000293:Adolescent; D000328:Adult; D001437:Bacteriuria / Q000175:diagnosis* / Q000652:urine; D002498:Centrifugation / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D015169:Colony Count, Microbial; D005260:Female; D005840:Gentian Violet; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000379:methods*; D010619:Phenazines; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000652:urine
chemical_list: C035863:Gram's stain; D010619:Phenazines; D005840:Gentian Violet