Can routine automated urinalysis reduce culture requests?

Kayalp, Damla; Doğan, Kübra; Ceylan, Gözde; Şeneş, Mehmet; Yücel, Doğan

doi:10.1016/j.clinbiochem.2013.06.015

Cited by 57 publications

(48 citation statements)

References 16 publications

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“…However, we found in the present study that most urine cultures produced negative results; to wit, Ͼ55% of all cultured samples produced no growth or clinically insignificant mixed Gram-positive growth, and similar results have been reported by others (31). A rapid bacteriuria test kit with high sensitivity and with high specificity, and with results available within the time frame of a patient visit, may serve as a useful tool in decreasing the need for expensive and laborious urine cultures by identifying samples likely to produce negative culture results.…”

Section: Discussionsupporting

confidence: 76%

Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

et al. 2015

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dUrinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by Escherichia coli and other Gram-negative uropathogens. We tested RapidBac, a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC), compared with standard bacterial culture using 966 clean-catch urine specimens submitted to a clinical microbiology laboratory in an urban academic medical center. RapidBac was performed in accordance with instructions, providing a positive or negative result in 20 min. RapidBac identified as positive 245/285 (sensitivity 86%) samples with significant bacteriuria, defined as the presence of a Gram-negative uropathogen or Staphylococcus saprophyticus at >10 3 CFU/ml. The sensitivities for Gram-negative bacteriuria at >10 4 CFU/ml and >10 5 CFU/ml were 96% and 99%, respectively. The specificity of the test, detecting the absence of significant bacteriuria, was 94%. The sensitivity and specificity of RapidBac were similar on samples from inpatient and outpatient settings, from male and female patients, and across age groups from 18 to 89 years old, although specificity was higher in men (100%) compared with that in women (92%). The RapidBac test for bacteriuria may be effective as an aid in the point-of-care diagnosis of UTIs especially in emergency and primary care settings. Bacterial urinary tract infections (UTIs) are a common clinical problem across the age spectrum in both genders (1). Women and girls are disproportionately affected by UTIs, with the lifetime risk estimated at Ͼ60% (2). In the United States, the overall annual cost of diagnosis and treatment of UTIs is considerable, estimated at $2.3 billion in 2010 (1). Gram-negative bacteria are the causative agents in up to 95% of uncomplicated UTIs in women, with Escherichia coli responsible for 70% to 90% (1).Diagnosis of UTI remains problematic in certain settings. The presence of uropathogenic bacteria in urine is the hallmark of UTI, and urine culture is the gold standard method for determination of clinically relevant bacteriuria. However, the 24-to 48-h delay in obtaining urine culture results has presented a longstanding need for more rapid diagnostic methods. Currently available rapid methods for detection of bacteriuria, including microscopy and test strips for detecting nitrite, have been shown to have poor sensitivity (3-5). A meta-analysis of 34 studies evaluating the accuracy of nitrite test strips across settings and populations found a mean sensitivity of 48% (using a definition of 10 5 CFU/ml for significant bacteriuria) (6). Microscopic urinalysis and urine Gram staining, two relatively laborious methods, have been shown by several studies to lack sensitivity below 10 5 CFU/ml and to have poor specificity (4,5,7,8). Guidelines for UTI from the Infectious Disease Society of America (IDSA) do not recommend urine culture for most cases of acute uncomplicated cystitis, the most common UTI presentation, and do not address laboratory methods for diagnosing UTI (9).An accurate ...

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Section: Discussionsupporting

confidence: 76%

Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

et al. 2015

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“…The newer analysers, which are better at counting bacteria, might be more suitable for a screening use as commented upon in some of the studies,45 46 53 but, in general, sensitivity is primarily influenced by the choice of the cut-off values. The process leading to the choice of possible or recommended cut-off values was not explicit or detailed in all the studies: ROC curves were often used to present the possible trade-off between sensitivity and specificity at various cut-off values,9 20 33 41 44–47 49 51–54 56 57 and the ROC analysis was often part of the strategy to assess the ‘optimal’ cut-off values. However, this approach can lead to problems, as some ROC curve analysis tools give equal value to false-positive and false-negative results and led to cut-off values with low sensitivities in some studies,53 54 whereas in screening tests, sensitivity is more important76 and, ideally, would be as high as 100% 77.…”

Section: Discussionmentioning

confidence: 99%

“…How quickly the microscopy was performed was reported in some studies in relation to the collection time, and it varied greatly ranging between 1 hour,7 52 2 hours,8 20 32 47 59–61 64 3 hours,63 4 hours,29 46 8 hours,53 10 hours10 and 24 hours 22 25 28 48 51. In other studies, the time for completing the microscopy was given in relation to the receipt time in the laboratory, and it ranged between 1 hour,11 18 30 31 33 35 2 hours,12 13 16 19 34 3 hours58 and 4 hours after receipt 21 24 62. In some of the studies, there was only a generic statement that urines had been tested without much delay9 17 27 38 39 50 54 56 65 or no clear statements 14 15 23 26 36 37 40–45 49 55 57…”

Section: Applicability Of the Validation Datamentioning

confidence: 99%

“…When exclusion criteria were mentioned, these were: catheter urines,33 36 38 45 46 urines obtained via invasive procedures such as suprapubic or ureteric samples,40 48 pregnant women,52 children <5 years old40 and neutropenic patients 40…”

Section: Applicability Of the Validation Datamentioning

confidence: 99%

“…A separate analysis may be required to prove the suitability of automated urine microscopy for certain patient categories such as children, but, of those studies with both adults and children, only one had a separate analysis for children 33. However, another four studies were exclusively paediatric studies: three assessed the use of automated microscopy as a screening tool,43 54 57 whereas the fourth one was aimed at identifying urine particles’ reference ranges 60…”

Section: Applicability Of the Validation Datamentioning

confidence: 99%

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Validation and verification of automated urine particle analysers

Bignardi

2016

J Clin Pathol

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There is often uncertainty on how validation and verification of newly introduced tests should be conducted, and there is a real risk of verification becoming a meaningless ritual, rather than a useful exercise. This article reviews the literature and makes recommendations regarding the validation and verification of automated urine particles analysers. A generic practical approach to verification is also recommended. For many analysers, the accuracy of white blood cells, epithelial cells and bacterial counts is corroborated by a number of independent evaluations; thus, any verification laboratory work could be significantly scaled down. Conversely, in the scenario that automated urine microscopy is used as a screening test to reduce the number of urines cultured, the extremely variable performance reported in the literature requires a full-scale verification to define the optimal cut-off values that give a sensitivity of >98% with the local settings and circumstances. With some analysers, the risk of carry-over also needs to be assessed, as part of the verification process, and exclusion criteria (urines requiring culture regardless of the microscopy results) need to be well defined, as there are patients or specimen types for which the performance of microscopy as a screening test may not be adequate.

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Utilization Management in the Routine Hematology Laboratory

Rudolf

Lewandrowski

2016

Utilization Management in the Clinical Laboratory and Other Ancillary Services

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Can routine automated urinalysis reduce culture requests?

Cited by 57 publications

References 16 publications

Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

Validation and verification of automated urine particle analysers

Utilization Management in the Routine Hematology Laboratory

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