UF-1000i™ flow cytometry is an effective screening method for urine specimens

Kadkhoda, K.; Manickam, K.; DeGagne, Pat; Sokolowski, Pat; Pang, Paulette; Kontzie, Nick; Alfa, Michelle J.

doi:10.1016/j.diagmicrobio.2010.09.013

Cited by 39 publications

(31 citation statements)

References 19 publications

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“…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.…”

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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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%

Validation and verification of automated urine particle analysers

Bignardi

2016

J Clin Pathol

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“…Nevertheless, results from earlier studies, which were done mostly with the flow cytometers of the Sysmex UF series, thus far have been mixed. While some authors have reported a fairly sufficient performance compared to urine culture (5)(6)(7)(8)(9)(10), others completely denied the feasibility of the automated devices as a screening tool, mostly due to an unacceptably large number of false-negative results (11,12). In addition, there is still an ongoing debate of what are the best cutoff values to discriminate samples in the positive and negative groups (10,11,13,14).…”

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confidence: 99%

Detection of Significant Bacteriuria by Use of the iQ200 Automated Urine Microscope

Stürenburg¹,

Kramer²,

Schön

et al. 2014

J Clin Microbiol

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cIn the microbiology laboratory, there is an augmented need for rapid screening methods for the detection of bacteria in urine samples, since about two-thirds of these samples will not yield any bacteria or will yield insignificant growth when cultured. Thus, a reliable screening method can free up laboratory resources and can speed up the reporting of a negative urine result. In this study, we have evaluated the detection of leukocytes, bacteria, and a new sediment indicator, the "all small particles" (ASP), by an automated instrument, the iQ200 urine analyzer, to detect negative urine samples that can be excluded from culture. A coupled automated strip reader (iChem Velocity), enabling the detection of nitrite and leukocyte esterase, was tested in parallel. In total, 963 urine samples were processed through both conventional urine culture and the iQ200/iChem Velocity workstation. Using the data, a multivariate regression model was established, and the predicted specificity and the possible reduction in urine cultures were calculated for the indicators and their respective combinations (leukocytes plus bacteria plus ASP and leukocyte esterase plus nitrite). Among all options, diagnostic performance was best using the whole microscopic content of the sample (leukocytes plus bacteria plus ASP). By using a cutoff value of >10 4 CFU/ml for defining a positive culture, a given sensitivity of 95% resulted in a specificity of 61% and a reduction in urine cultures of 35%. By considering the indicators alone, specificity and the culture savings were both much less satisfactory. The regression model was also used to determine possible cutoff values for running the instrument as part of daily routine. By using a graphical representation of all combinations possible, we derived cutoff values for leukocyte, bacterial, and ASP count, which should enable the iQ200 microscope to screen out approximately one-third of the urine samples, significantly reducing the workload in the microbiology laboratory.

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“…With the review rules of UF-1000i expert software, the review rate was 32 % (160/500) in the test set. Although papers on the evaluation of UF-1000i have been reported (1,4,21,22) , they did not give the detail review rules in their study. Since UF-1000i is an improvement on UF-100, two Red circle represents the optimal probability of UrineCART for maximum sensitivity, acceptable specifi city and total review rate.…”

Section: Comparison To the Other Microscopic Review Rulesmentioning

confidence: 95%