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Updated: Feb 7, 2026

Cell-Free DNA Integrity Analysis in Urine Samples
Published on: January 5, 2017
Urine Xanthine Crystals in Tumor Lysis Syndrome
Ayumi Omokawa1, Mariko Oguma2, Shigeharu Ueki1
1Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
Abstract:
Urine xanthine crystals are remarkably rare but can be observed by routine urine microscopy. We report the results of a 67-year-old man with T-cell-prolymphocytic leukemia whose urine contained xanthine crystals after chemotherapy and prophylactic administration of febuxostat. Accumulation of xanthine was due to tumor lysis syndrome causing a massive release of DNA. The metabolized DNA caused an increase of xanthine, which was not readily converted to uric acid by xanthine oxidase because of febuxostat inhibition of this enzyme.
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