Siedner Mark J, Gelber Allan C, Rovin Brad H, McKinley Alison M, Christopher-Stine Lisa, Astor Brad, Petri Michelle, Fine Derek M
Columbia University College of Physicians and Surgeons, New York, NY, USA.
J Rheumatol. 2008 Jan;35(1):84-90. Epub 2007 Dec 15.
Early detection of renal involvement in lupus prevents poor outcomes. Although published guidelines recommend urine dipstick as an appropriate screening test and evidence suggests a majority of American rheumatologists use dipstick to screen for proteinuria, the performance of this diagnostic approach in lupus has not been reported. We examined the validity of qualitative urine dipstick versus quantitative 24-hour measurement to accurately detect proteinuria, including low-level proteinuria.
We performed a diagnostic accuracy study using paired samples from the Johns Hopkins University School of Medicine and the Ohio State University School of Medicine lupus cohorts. All qualitative urine dipstick values were obtained within 1 day of a 24-hour urine collection.
We analyzed the performance of 3 urine dipstick assays to detect proteinuria compared to 24-hour protein/creatinine ratios, using 2224 dipstick measures from 296 patients. The sensitivity of a > or = 1+ dipstick result to detect quantitative proteinuria (> or = 0.50 g protein/g creatinine) was 82.7% for the Clinitek, 97.7% for the Atlas, and 85.5% for the Bayer assay. The corresponding sensitivity to detect low-level proteinuria, (0.50-0.99 g protein/g creatinine) was 63.1%, 96.4%, and 80.7%, respectively. The specificity to correctly exclude proteinuria (< 0.50 g protein/g creatinine) with negative/trace results was 86.1%, 62.2%, and 59.4%. There was considerable variability in the range of protein/creatinine ratios detected at each dipstick level of proteinuria.
Urine dipsticks demonstrate substantial variability and often poor validity to accurately detect proteinuria at quantitative levels; this warrants further diagnostic evaluation. Clinicians should consider quantified proteinuria assays as a more accurate screening tool in the diagnostic evaluation of lupus nephritis.
早期发现狼疮性肾炎可预防不良预后。尽管已发布的指南推荐尿试纸法作为一种合适的筛查试验，且有证据表明大多数美国风湿病学家使用尿试纸法筛查蛋白尿，但该诊断方法在狼疮中的表现尚未见报道。我们比较了定性尿试纸法与定量24小时测量法准确检测蛋白尿（包括低水平蛋白尿）的有效性。
我们使用来自约翰霍普金斯大学医学院和俄亥俄州立大学医学院狼疮队列的配对样本进行了一项诊断准确性研究。所有定性尿试纸检测值均在24小时尿液收集的1天内获得。
我们分析了3种尿试纸检测法检测蛋白尿的性能，并与24小时蛋白/肌酐比值进行比较，共使用了来自296例患者的2224次尿试纸检测结果。对于检测定量蛋白尿（≥0.50g蛋白/g肌酐），Clinitek检测法的≥1+尿试纸结果的敏感性为82.7%，Atlas检测法为97.7%，拜耳检测法为85.5%。检测低水平蛋白尿（0.50 - 0.99g蛋白/g肌酐）的相应敏感性分别为63.1%、96.4%和80.7%。阴性/微量结果正确排除蛋白尿（<0.50g蛋白/g肌酐）的特异性分别为86.1%、62.2%和59.4%。在每个蛋白尿试纸检测水平检测到的蛋白/肌酐比值范围存在相当大的差异。
尿试纸法在准确检测定量水平的蛋白尿方面表现出很大的变异性且有效性往往较差；这需要进一步的诊断评估。在狼疮性肾炎的诊断评估中，临床医生应将定量蛋白尿检测法视为更准确的筛查工具。
