Erroneous point of care hyperglycemia in a preterm due to ascorbic acid administration

BackgroundHyperglycemia is a commonly encountered problem in the NICU. In some cases, after extensive investigation, no specific etiology can be attributed. We report a case of persistently high general random blood sugar (GRBS) readings for which no medical or clinical cause could be determined, but the lab estimate of concurrent blood sugar was normal.Case descriptionIn a recent case involving an extremely premature infant (24 weeks), we observed that GRBS readings on glucometers were found to be persistently high on multiple occasions on day 26 of life. The baby was investigated and ruled out sepsis, iatrogenic, and other causes. However, concurrent serum blood sugars showed normal values with a normal urine routine. The glucometer calibration was checked, and the GRBS readings obtained from the other babies on the same glucometer were normal. This led us to think of other possible reasons and given the disparity between glucometer GRBS readings and serum blood sugars from the lab, further literature searches were done, and it was found that the glucometer mistakenly misinterprets ascorbic acid as glucose due to their comparable molecular weight. This baby was receiving IV ascorbic acid for methemoglobinemia.ConclusionThis was a new learning experience for us, and we wanted to share it with our neonatal fraternity. This case further illustrates the need to be aware of the side effects of all medications we use. Also, it is imperative to investigate deeply into the reason for certain disparities in the reports, especially with point-of-care testing.