Finger-Stick Artifactual Hypoglycemia in the Emergency Department: A Case Report

Artifactual hypoglycemia is a low glucose measurement in a normoglycemic patient. Patients in a shock state or with extremity hypoperfusion can metabolize a higher proportion of the glucose in the poorly perfused tissue, and blood obtained from those tissues may have far lower glucose concentration than the blood in the central circulation.

We present the case of a 70-year-old woman with systemic sclerosis, progressive functional decline, and cool digital extremities. The initial point-of-care testing (POCT) for glucose was 55 mg/dL from her index finger, with subsequent repeated low POCT glucose reading, despite glycemic repletion and contradictory euglycemic serologic readings from her peripheral i.v. sites. Two separate POCTs were then obtained from her finger and her antecubital fossa, which had vastly different glucose readings; the latter was in congruence with her i.v. draws. The patient was diagnosed with artifactual hypoglycemia. Alternative sources of blood to avoid artifactual hypoglycemia on POCT samples are discussed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Artifactual hypoglycemia is a rare but commonly misdiagnosed phenomenon that can occur in emergency department patients when peripheral perfusion is limited. We encourage physicians to confirm peripheral capillary results with a venous POCT or explore alternative sources of blood to avoid artificial hypoglycemia. Small absolute errors can matter when the erroneous result is hypoglycemia.