A 63-year-old man with metastatic lung cancer admitted for severe hip pain and malaise was noted to have erratic daily morning plasma glucose concentrations, with several critical values below 40 mg/dL (<2.2 mmol/L). Each time he had a critically low laboratory glucose value, a point-of-care finger-stick glucose was found to be within reference intervals. The remaining chemistry results were notable for occasional mild hypocalcemia and hypophosphatemia. He exhibited no clinical signs of hypoglycemia and work-up for infection was negative.

Questions

  1. Which values are likely correct, the finger-stick glucose or the plasma glucose?
  2. What can cause falsely low plasma glucose?
  3. What can be done to prevent the falsely low glucose measurements?
Read the article here for the answers