The Poison Pen: Bedside Diagnosis of Urinary Diquat

Department of Emergency Medicine, UCSF-Fresno Medical Center, 155 N. Fresno Drive, Fresno, CA 93701, USA.
Journal of medical toxicology: official journal of the American College of Medical Toxicology 03/2010; 6(1):35-6. DOI: 10.1007/s13181-010-0033-6
Source: PubMed


Diquat is a bipyridyl herbicide with nephrotoxic effects. This in vitro study demonstrates a colorimetric test for detection of diquat in human urine. Urine specimens using ten concentrations of diquat herbicide solution and controls for urine and glyphosate were prepared. A two-step assay (addition of bicarbonate followed by sodium dithionite) was performed, with a resulting color change of the original solution for each specimen. Color change intensity was noted immediately and after 30 min, by gross visual inspection. A green color with concentration-dependent intensity was detected in all specimens, in which concentrations of diquat solution ranged from 0.73 to 730 mg/L. This colorimetric effect disappeared after 30 min. The sodium bicarbonate/dithionite test may be useful as a qualitative bedside technique for the detection of urinary diquat in the appropriate clinical setting.

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