Objective: To create awareness among health care professionals and nurses regarding interference with point-of-care (POC) blood glucose (BG) meter by high-dose intravenous vitamin C and other potential substances. We report a case that probably resulted in the death of a patient from an erroneous interpretation of POC-BG readings due to interference from high-dose vitamin C. Methods: Retrospective case review Results: Our patient was admitted following a syncopal episode associated with an acute non-ST elevation myocardial infarction. She was found to have significant hyperglycemia with blood glucose >600 mg/dL on POC testing, associated with moderate ketoacidosis. She was treated with intravenous insulin as a case of diabetic ketoacidosis (DKA). She developed severe hypoglycemia, which was confirmed on a venous BG, and her condition was complicated by an apparent stroke-like state. The patient deteriorated and subsequently died. We found no report of vitamin C causing apparent DKA, as seen in our case. Conclusion: POC-BG monitoring is very commonly used in intensive care unit settings to monitor BG as they are minimally invasive, convenient, and quick. However, physicians and nurses need to be aware that certain substances can interfere with and alter POC-BG levels, leading to incorrect diagnosis of pseudohyperglycemia or pseudohypoglycemia. This may potentially lead to catastrophic consequences and result in increased morbidity and mortality in intensive care unit settings. The Food and Drug Administration advises against the use of POC-BG meters in critical settings, and they should never be used to diagnose DKA.