Test characteristics of the urine Gram stain in infants ≤ 60 days of age with fever

Dayan, Peter; Bennett, Jonathan E.; Best, R. Russell; Bregstein, J S; Levine, D.F.; Novick, M K; Sonnett, F M; Stimell-Rauch, M L; Urtecho, Jacqueline; Wagh, Amarjeet; Miller, Stacey

doi:10.1097/00006565-200202000-00004

Cited by 33 publications

(38 citation statements)

References 8 publications

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“…Two of these were also included in our review, 177,178 and one was excluded 179 as it was based on secondary care. The review is therefore not considered further and this synthesis focuses instead on the eight primary studies.…”

Section: Nappy Padsmentioning

confidence: 99%

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

Hay

Birnie²,

Busby³

et al. 2016

Health Technol Assess

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BackgroundIt is not clear which young children presenting acutely unwell to primary care should be investigated for urinary tract infection (UTI) and whether or not dipstick testing should be used to inform antibiotic treatment.ObjectivesTo develop algorithms to accurately identify pre-school children in whom urine should be obtained; assess whether or not dipstick urinalysis provides additional diagnostic information; and model algorithm cost-effectiveness.DesignMulticentre, prospective diagnostic cohort study.Setting and participantsChildren < 5 years old presenting to primary care with an acute illness and/or new urinary symptoms.MethodsOne hundred and seven clinical characteristics (index tests) were recorded from the child’s past medical history, symptoms, physical examination signs and urine dipstick test. Prior to dipstick results clinician opinion of UTI likelihood (‘clinical diagnosis’) and urine sampling and treatment intentions (‘clinical judgement’) were recorded. All index tests were measured blind to the reference standard, defined as a pure or predominant uropathogen cultured at ≥ 105colony-forming units (CFU)/ml in a single research laboratory. Urine was collected by clean catch (preferred) or nappy pad. Index tests were sequentially evaluated in two groups, stratified by urine collection method: parent-reported symptoms with clinician-reported signs, and urine dipstick results. Diagnostic accuracy was quantified using area under receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) and bootstrap-validated AUROC, and compared with the ‘clinician diagnosis’ AUROC. Decision-analytic models were used to identify optimal urine sampling strategy compared with ‘clinical judgement’.ResultsA total of 7163 children were recruited, of whom 50% were female and 49% were < 2 years old. Culture results were available for 5017 (70%); 2740 children provided clean-catch samples, 94% of whom were ≥ 2 years old, with 2.2% meeting the UTI definition. Among these, ‘clinical diagnosis’ correctly identified 46.6% of positive cultures, with 94.7% specificity and an AUROC of 0.77 (95% CI 0.71 to 0.83). Four symptoms, three signs and three dipstick results were independently associated with UTI with an AUROC (95% CI; bootstrap-validated AUROC) of 0.89 (0.85 to 0.95; validated 0.88) for symptoms and signs, increasing to 0.93 (0.90 to 0.97; validated 0.90) with dipstick results. Nappy pad samples were provided from the other 2277 children, of whom 82% were < 2 years old and 1.3% met the UTI definition. ‘Clinical diagnosis’ correctly identified 13.3% positive cultures, with 98.5% specificity and an AUROC of 0.63 (95% CI 0.53 to 0.72). Four symptoms and two dipstick results were independently associated with UTI, with an AUROC of 0.81 (0.72 to 0.90; validated 0.78) for symptoms, increasing to 0.87 (0.80 to 0.94; validated 0.82) with the dipstick findings. A high specificity threshold for the clean-catch model was more accurate and less costly than, and as effective as, clinical judgement. The additional diagnostic utility of dipstick testing was offset by its costs. The cost-effectiveness of the nappy pad model was not clear-cut.ConclusionsClinicians should prioritise the use of clean-catch sampling as symptoms and signs can cost-effectively improve the identification of UTI in young children where clean catch is possible. Dipstick testing can improve targeting of antibiotic treatment, but at a higher cost than waiting for a laboratory result. Future research is needed to distinguish pathogens from contaminants, assess the impact of the clean-catch algorithm on patient outcomes, and the cost-effectiveness of presumptive versus dipstick versus laboratory-guided antibiotic treatment.FundingThe National Institute for Health Research Health Technology Assessment programme.

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Section: Nappy Padsmentioning

confidence: 99%

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

Hay

Birnie²,

Busby³

et al. 2016

Health Technol Assess

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show abstract

“…45,47,53,55,59,60,62,70,[72][73][74][75]78,81,84,89,91,101,105,[110][111][112]230 More than half (17/23) of these studies did not include an appropriate spectrum of patients, and patient selection criteria were often inadequately described. Avoidance of test review bias was poorly reported; 14 out of the 23 studies did not report whether those interpreting results were blinded to the results of other tests.…”

Section: Nitritementioning

confidence: 99%

Clinical effectiveness and cost-effectiveness of tests for the diagnosis and investigation of urinary tract infection in children: a systematic review and economic model

Whiting¹,

Westwood²,

Bojke³

et al. 2006

Health Technol Assess

133

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The results of the systematic review were used to derive an algorithm for the diagnosis of UTI in children under 5. This algorithm represents the conclusions of the review in terms of effective practice. There were insufficient data to propose an algorithm for the further investigation of UTI in children under 5. The quality assessment highlighted several areas that could be improved upon in future diagnostic accuracy studies.

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“…The 90.8% sensitivity of laboratoryperformed dipstick in this study is higher than previous estimates of 75% to 85%. 9,16,26,27 However, these other studies defined UTI at a lower threshold of $10 000 CFUs per mL and/or emphasized infants and children older than 90 days.Our study has several limitations. Data analysis was retrospectively performed from a data set collected for other purposes.…”

mentioning

confidence: 99%

Dipstick Screening for Urinary Tract Infection in Febrile Infants

Glissmeyer¹,

Korgenski

Wilkes

et al. 2014

Pediatrics

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WHAT'S KNOWN ON THIS SUBJECT: Urinary tract infection (UTI) is the most common bacterial infection in febrile infants aged 1 to 90 days. It is unclear if urine microscopy offers significant benefit beyond urine dipstick as a screening test for UTI in this population.WHAT THIS STUDY ADDS: Dipstick may be an adequate screening test for UTI in infants aged 1 to 90 days with a negative predictive value (NPV) of 98.7%. Adding microscopy increases the NPV to 99.2% but results in 8 false-positives for every UTI missed by dipstick.abstract OBJECTIVE: This study compares the performance of urine dipstick alone with urine microscopy and with both tests combined as a screen for urinary tract infection (UTI) in febrile infants aged 1 to 90 days. METHODS:We queried the Intermountain Healthcare data warehouse to identify febrile infants with urine dipstick, microscopy, and culture performed between 2004 and 2011. UTI was defined as .50 000 colonyforming units per milliliter of a urinary pathogen. We compared the performance of urine dipstick with unstained microscopy or both tests combined ("combined urinalysis") to identify UTI in infants aged 1 to 90 days. RESULTS:Of 13 030 febrile infants identified, 6394 (49%) had all tests performed and were included in the analysis. Of these, 770 (12%) had UTI. Urine culture results were positive within 24 hours in 83% of UTIs. The negative predictive value (NPV) was .98% for all tests. The combined urinalysis NPV was 99.2% (95% confidence interval: 99.1%-99.3%) and was significantly greater than the dipstick NPV of 98.7% (98.6%-98.8%). The dipstick positive predictive value was significantly greater than combined urinalysis (66.8% [66.2%-67.4%] vs 51.2% [50.6%-51.8%]). These data suggest 8 febrile infants would be predicted to have a false-positive combined urinalysis for every 1 infant with UTI initially missed by dipstick screening.CONCLUSIONS: Urine dipstick testing compares favorably with both microscopy and combined urinalysis in febrile infants aged 1 to 90 days. The urine dipstick test may be an adequate stand-alone screen for UTI in febrile infants while awaiting urine culture results. Pediatrics 2014;133:e1121-e1127 UTI screening methods may include dipstick urinalysis and/or microscopy of centrifuged urine, as well as other methods. 3,4,[9][10][11] Urine dipstick is an inexpensive and rapid screening test that can be performed in office settings and other laboratories and is waived by the Clinical Laboratory Improvement Amendment (CLIA). 12 Dipstick has been shown to perform well in children $2 years old as a screening test for UTI. 13 Microscopic examination of urine requires technicians with special training in laboratories using CLIA-certified methods. 12 Previous studies have questioned the additional benefit of microscopy over dipstick urinalysis in children; however, these studies included few infants 1 to 90 days of age. [14][15][16][17][18][19][20] Although dipstick is rapid, inexpensive, and does not require special training, there currently are insufficient data t...

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Test characteristics of the urine Gram stain in infants ≤ 60 days of age with fever

Abstract: The Gram stain has excellent test characteristics for the preliminary diagnosis of a UTI in febrile infants. Patient disposition and therapy will likely change if clinical protocols and guidelines use the Gram stain rather than urine microscopy for preliminary diagnosis of UTI in infants.

Cited by 33 publications

References 8 publications

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

Clinical effectiveness and cost-effectiveness of tests for the diagnosis and investigation of urinary tract infection in children: a systematic review and economic model

Dipstick Screening for Urinary Tract Infection in Febrile Infants

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