Interference of high dose intravenous vitamin C with blood glucose testing in a patient with COVID-19 infection

Flash glucose monitoring system (FGMs) is an option for patients to monitor their glucose however, the presence of interfering substances can result in false blood glucose readings. The COVID-19 (SARS-2-Cov) pandemic has resulted in substantial damage to the public and currently, no effective treatment is available for this deadly disease. Intravenous vitamin C (VC) has been shown to attenuate the cytokine storm in COVID-19 infection. Studies suggest that vitamin C supplementation reduces blood glucose in diabetic patients. On the other hand, VC can affect glucose readings obtained by devices in varying degrees. Here, we present a diabetic patient diagnosed with COVID-19 infection, who had false increased blood glucose readings on FGM after VC treatment. A 45-year-old woman with T2DM was diagnosed with a COVID-19 infection. Intravenous VC at a dose of 2500mg five times was added to the standard treatment protocol due to COVID-19 pneumonia. Her flash glucose levels were consistently elevated during intravenous VC infusion and returned to her normal average values after cessation of infusion. Insulin was not given at the time of fluctuations in blood glucose readings because both fingerstick and venous blood glucose measurements at the time of VC infusion were not consistent with the FGM readings. False increase in blood glucose readings due to interfering substances should be kept in mind since correction with insulin or antidiabetics may lead to a potential for dangerous life-threatening hypoglycemic events.

Keywords:

Flash Glucose Monitoring system, COVID-19 interference, high dose vitamin C,

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