In a previous post I talked about the need for reproducibility and accuracy in multiplexed bioassays but report in today’s NY Times made clear the enormity of the problem even when a single analyte is measured. The key points from the report “Standards Might Rise on Monitors for Diabetics” are
- In United States 18 million peoples have Diabetes and another 6 million are expected to have it without knowing
- More than 11 million diabetic in Unites States use Glucose monitors
- Tight control of blood glucose level resulted in 76, 54 and 60% reduction in the risk for retinopathy, albuminuria and clinical neuropathy respectively
- International Standard Organization (ISO) allows 20% variation in strip based blood glucose monitor when glucose values are >75mg/dl and values must be within 15mg/dl when Glucose values are less than 75mg/dl. ISO Document#15197 “In vitro diagnostic test systems — Requirements for blood-glucose monitoring systems for self-testing in managing diabetes mellitus”
- FDA analysis has however showed that stricter standards of 15% variation can be met by most manufacturer
Strip based glucose monitors can give erroneous results under various conditions including
- In presence of Tylenol, vitamin C or sugar such as Xylose or mannose
- At high temperature, humidity, altitude
- When blood is taken from alternate site like thigh or forearm
- Mishandling of strip or instrument
- A study by government researchers found that when comparing tests from five different popular monitors, results varied by as much as 32 percent
- A stricter requirement on quality control will increase the price of the testing and may discourage regular testing and hence increase the risk.
- FDA however agrees that testing of Glucose as biomarkers for diagnosis in ICUs and hospital environment should be done by non-strip based systems with accuracy approaching laboratory based systems
- Continuous training and awareness is required for proper use of glucose monitoring devices
Though FDA/ISO guidelines and specific need for meeting quality standards may be common knowledge for diagnostic companies it is important that research/academic laboratories developing Biosensing technologies, IVDs and POCs must be aware of these requirements early on to ensure translation of research into practice.