How does contamination by urostomy pouch skin barriers affect urinary sediment determination?

Abstract

Many contaminants other than components derived from the urinary tract are present when performing urinary sediment examination. Skin barriers attached to the urostomy pouch after urinary diversion surgery also contaminate urinary sediments, but reports on its components are few. We investigated the effects of four types of skin barrier (CPGFb, CPGbs, CPbh, and CPGHbs) used in our hospital on urinary sediment examination. The components commonly observed in urinary sediments from patients using these skin barriers were unstructured cast-like and near-circular components. Fibrous components were observed in patients using CPGFb-based skin barriers, and capsule-like components were observed in patients using CPGHbs-based skin barriers. Cast-like components were similar to hyaline casts and waxy casts in urinary sediments, and capsule-like components were similar to food residues in feces. When feces are observed in urinary sediments, contamination during urine collection or an intestinal fistula is suspected. However, feces in urine after urinary diversion surgery is an unlikely contaminant during urine collection. It is conceivable that capsule-like components from skin barriers may be misidentified as feces and lead to the clinical suspicion of an intestinal fistula. Morphologically distinguishing between feces and capsule-like components derived from skin barriers is difficult. The following points were useful in distinguishing between capsule-like components from skin barriers and feces: capsule-like components derived from skin protective agents are unstained and colorless, various fecal components other than the capsule-like components are not observed, and the patient is known to use CPGHbs skin barriers. Contamination by skin barriers should be considered when performing urinary sediment examinations.