Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores

Little, Paul, Turner, Sheila, Rumsby, Kate, Warner, Greg, Moore, Michael. J, Lowes, Andrew, Smith, Helen, Hawke, Catherine and Mullee, Mark (2006) Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores. British Journal of General Practice, 56. pp. 606-612. ISSN 0960-1643

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Abstract

Background Suspected urinary tract infection (UTI) is one of the most common presentations in primary care. Systematic reviews have not documented any adequately powered studies in primary care that assess independent predictors of laboratory diagnosis. Aim To estimate independent clinical and dipstick predictors of infection and to develop clinical decision rules. Design of study Validation study of clinical and dipstick findings compared with laboratory testing. Setting General practices in the south of England. Method Laboratory diagnosis of 427 women with suspected UTI was assessed using European urinalysis guidelines. Independent clinical and dipstick predictors of diagnosis were estimated. Results UTI was confirmed in 62.5% of women with suspected UTI. Only nitrite, leucocyte esterase (+ or greater), and blood (haemolysed trace or greater) independently predicted diagnosis (adjusted odds ratios 6.36, 4.52, 2.23 respectively). A dipstick decision rule, based on having nitrite, or both leucocytes and blood, was moderately sensitive (77%) and specific (70%); positive predictive value (PPV) was 81% and negative predictive value (NPV) was 65%. Predictive values were improved by varying the cut-off point: NPV was 73% for all three dipstick results being negative, and PPV was 92% for having nitrite and either blood or leucocyte esterase. A clinical decision rule, based on having two of the following: urine cloudiness, offensive smell, and dysuria and/or nocturia of moderate severity, was less sensitive (65%) (specificity 69%; PPV 77%, NPV 54%). NPV was 71% for none of the four clinical features, and the PPV was 84% for three or more features. Conclusions Simple decision rules could improve targeting of investigation and treatment. Strategies to use such rules need to take into account limited negative predictive value, which is lower than expected from previous research.

Item Type: Article
Keywords: clinical scoring algorithms, diagnosis, urinary tract infection, dipsticks
Schools and Departments: Brighton and Sussex Medical School > Primary Care and Public Health
Brighton and Sussex Medical School > Brighton and Sussex Medical School
Subjects: R Medicine > R Medicine (General)
R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine
Depositing User: Caroline Brooks
Date Deposited: 08 Apr 2010
Last Modified: 13 Mar 2017 11:56
URI: http://sro.sussex.ac.uk/id/eprint/2285
Google Scholar:28 Citations

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