The performance of fully automated urine analysis results for predicting the need of urine culture test

Abstract

Objectives: Urinalysis and urine culture are most common tests for diagnosis of urinary tract infections. The aim of our study is to examine the diagnostic performance of urine analysis and the role of urine analysis to determine the requirements for urine culture. Methods: Urine culture and urine analysis results of 362 patients were retrospectively analyzed. Culture results were taken as a reference for chemical and microscopic examination of urine and diagnostic accuracy of the test parameters, that may be a marker for urinary tract infection, and the performance of urine analysis were calculated for predicting the urine culture requirements. Results: A total of 362 urine culture results of patients were evaluated and 67% of them were negative. The results of leukocyte esterase and nitrite in chemical analysis and leukocytes and bacteria in microscopic analysis were normal in 50.4% of culture negative urines. In diagnostic accuracy calculations, leukocyte esterase (86.1%) and microscopy leukocytes (88.0%) were found with high sensitivity, nitrite (95.4%) and bacteria (86.6%) were found with high specificity. The area under the curve was calculated as 0.852 in ROC analysis for microscopic examination for leukocytes. Conclusion: Full-automatic urine devices can provide sufficient diagnostic accuracy for urine analysis. The evaluation of urine analysis results in an effective way can predict the necessity for urine culture requests and especially may contribute to a reduction in the work load and cost. J Clin Exp Invest 2014; 5 (2): 286-289

Keywords

• Urine analysis, urine culture, sensitivity, specificity

İdrar kültürü testi gerekliliğini öngörmede tam otomatik idrar analizi sonuçlarının performansı

Öz

Amaç: Tam idrar analizi ve idrar kültürü idrar yolu enfeksiyonlarının tanısı için sıklıkla yapılan incelemelerdendir. Çalışmamızın amacı tam idrar analizinin tanısal performansını ve idrar kültürü gerekliliğini belirlemedeki rolünü incelemektir. Yöntemler: İdrar kültürü ve tam idrar analizi sonucu olan 362 hasta sonucu retrospektif olarak incelendi. Kültür sonuçları referans kabul edilerek, idrarın kimyasal ve mikroskopik incelemesinde, idrar yolu enfeksiyonu göstergesi olabilecek testlerin tanısal doğruluk parametreleri hesaplandı ve kültür istemini öngörmedeki performansı değerlendirildi. Bulgular: Toplam 362 hastaya ait idrar kültürü sonuçlarının %67 si negatifti ve bu kültür sonucu negatif olan örneklerin %50,4 ünde kimyasal analizde lökosit esteraz, nitrit ve mikroskopik analizde lökosit ve bakteri sonuçları normal olarak bulundu. Tanısal doğruluk hesaplamalarında, lökosit esteraz (%86,1) ve mikroskopide lökosit (%88,0) testlerinin sensitiviteleri yüksek bulunurken, nitrit (%95,4) ve bakteri (%86,6) incelemelerinin spesifiteleri yüksek bulundu. Mikroskopide lökosit incelemesi için yapılan ROC analizinde eğri altındaki alan 0,852 olarak hesaplandı. Sonuç: Tam otomatik idrar cihazları, tam idrar analizi için yeterli tanısal doğruluğu sağlayabilmektedir. Tam idrar analizi sonuçlarının etkin bir şeklide değerlendirilmesi kültür istemleri için gerekliliği öngörebilir ve laboratuvarlarda özellikle iş yükü ve maliyetin azalmasına katkı sağlayabilir.

Anahtar Kelimeler

• Tam idrar analizi, idrar kültürü, sensitivite, spesifite

Kaynakça

1. Kayalp D, Dogan K, Ceylan G, et al. Can routine au- tomated urinalysis reduce culture requests? Clin Bio- chem 2013;46:1285–1289.
2. Devillé WLJM, Yzermans JC, van Duijn NP, et al. The urine dipstick test useful to rule out infections. A meta- analysis of the accuracy. BMC Urol 2004:2;4:4.
3. Whiting P, Westwood M, Bojke L, et al. Clinical effec- tiveness and cost-effectiveness of tests for the di- agnosis and investigation of urinary tract infection in children: a systematic review and economic model. Health Technology Assessment 2006;10:36
4. Yüksel H, Kiliç E, Ekinci A, Evliyaoğlu O. Comparison of fully automated urine sediment analyzers H800- FUS100 and Labumat-Urised with Manual Micros- copy. J Clin Lab Anal 2013;27:312–316.
5. Luciano R, Piga S, Federico L, et al. Development of a score based on urinalysis to improve the manage- ment of urinary tract infection in children. Clin Chim Acta 2012;413:478–482.
6. Young JL, Soper DE. Urinalysis and urinary tract infec- tion: update for clinicians. Infect Dis Obstet Gynecol 2001;9:249–255.
7. Okada H, Sakai Y, Miyazaki S, et al. Detection of Signif- icant Bacteriuria by Automated Urinalysis Using Flow Cytometry. J Clin Microbiol 2000;38:2870–2872.
8. Martinez MHM, Bottini PV, Levy CE, Garlipp CR. UriSed as a screening tool for presumptive diagnosis of uri- nary tract infection. Clin Chim Acta 2013;425:77–79.

9. Sivathasan N, Rakowski KR. Microscopy, culture, and sensitive management of uncomplicated urinary tract infections in adults in the primary care setting. Saudi Med J 2011;32:559–562.
10. Gülcan A, Çalik G, Gülcan E, et al. Performance eval- uation of urinalysis and culture results in patients sus- pected urinary tract infection. Abant Medical Journal doi: 10.5505/abantmedj.2012.47955
11. European Confederation of Laboratory Medicine. Eu- ropean urinalysis guidelines. Scand J Clin Lab Inves- tig Suppl 2000;231:1–86.