Mass spectrometry analysis of urine and catheter of a patient with purple urinary bag syndrome

INTRODUCTION: Purple urinary bag syndrome (PUBS) is considered to be a benign condition observed in the urinary catheter and bag in some catheterized patients with urinary tract infections. This syndrome is usually reported to occur in alkaline urine. CASE REPORT: We report of a catheterized patient with PUBS and slightly acidic urine (pH 6-6.5). A novel analysis method was developed using high pressure liquid chromatography and mass spectrometry (HPLC/MS) to detect compounds that are thought to be associated with PUBS. Urine, urinary sediment, and the plastic collection system were assayed and quantitated using these methods. The potential toxicity of one of these compounds, indoxyl sulfate, is discussed. CONCLUSIONS: The presence of PUBS in a catheterized patient with slightly acidic urine is reported. A novel method for the analysis of chemical components of PUBS and the first direct confirmation of the presence of indigo in the urine sediment and collecting system are described.