Vitamin C and aberrant electrolyte results.

Vitamin C interferes with assays involving the redox-reaction. However, the interference of Vitamin C with electrolytes has not been reported. In the present case, we describe a 61-year-old lady with severe electrolyte abnormalities after administration of high doses of vitamin C. This patient, who had terminal colon cancer, presented to hospital with anuria. Her electrolytes were extremely abnormal (determined on the Beckman Synchron LX20): serum sodium 200 mmol/L, potassium 7.0 mmol/L, and chloride 50 mmol/L. Repeated measurements showed similar abnormalities. However, these critical abnormalities did not fit her clinical picture, as she was alert with normal vital signs. One of the specimens was also run on both the ABL700 and the Bayer644 analyzers, and the electrolytes appeared normal. Pooled serum from healthy individuals to which various amounts of vitamin C was added then was analyzed on Beckman Synchron LX20 for electrolytes, demonstrating the interference of vitamin C consistent with the initial finding. Thus, we eventually figured out that the aberrant results were due to the vitamin C caused analytical interference.