Evaluation of common urine leukocyte dipsticks for diagnosing peritoneal dialysis (PD)-associated peritonitis

Abstract

BackgroundPeritonitis is a severe complication in peritoneal dialysis (PD), necessitating prompt diagnosis and treatment. A key diagnostic indicator is elevated white blood cells (WBC) in spent PD effluent. Laboratory-based WBC testing can be slow, costly, and infrastructure-dependent, potentially delaying treatment. Urine dipsticks, commonly used for urinary tract infections, include a leukocyte esterase (LE) test that may serve as a rapid and low-cost point-of-care alternative. We evaluated the effectiveness of using an LE test of urine dipsticks to detect WBC in PD effluent for diagnosing PD-associated peritonitis.MethodsOur research comprised a clinical and a laboratory part. Clinically, we analyzed data from Khartoum, Sudan, where LE dipsticks are routinely given to PD patients for point-of-care testing of PD effluent. In a laboratory, we compared dipstick results with WBC counts in stored, freeze-thawed PD effluents from Australia and the United States, and evaluated smartphone imaging of dipstick coloration.ResultsThe clinical evaluation comprised 56 pediatric PD patients providing 530 PD effluent samples. Dipstick LE testing of freshly collected effluents demonstrated 100% sensitivity and 100% specificity for peritonitis diagnosis. In the laboratory study, testing of 352 freeze-thawed PD effluents showed reduced sensitivity (78%) and specificity (95%) after 1 month of refrigerator storage. Smartphone imaging reliably supported visual inspection and enabled semi-quantitative color assessment.ConclusionsWhen used on freshly collected PD effluents, the LE test on urine dipsticks is a rapid, reliable, and affordable tool for diagnosing PD-associated peritonitis. This approach is particularly valuable in low-resource settings, home-based care, and telehealth.