A 78-year-old man uses a continuous glucose monitor; a new sensor shows persistently high readings compared with finger-prick tests. What is the most appropriate action?

• A. Replace the sensor and report the problem via Yellow Card
• B. Contact the device manufacturer for a fault report
• C. Use fingerstick only until reviewed
• D. Ignore the fault

Answer: (A)

When a medical device gives readings that don’t match a validated method, safety first means addressing the device fault and informing regulators. A CGM that consistently reads higher than finger-prick tests likely has a faulty sensor. Replacing the sensor removes the immediate source of erroneous data, reducing the risk of incorrect treatment decisions based on faulty readings. At the same time, reporting the issue via the Yellow Card scheme helps pharmacovigilance and device safety surveillance, so regulators can identify patterns and take action if needed.

Choosing to contact the manufacturer alone doesn’t directly mitigate the immediate risk to the patient, and ignoring the fault is unsafe. Relying on fingerstick only temporarily might help cross-check readings, but it doesn’t fix the faulty sensor or contribute to broader safety monitoring.