Blood Glucose Meter Use in Critically Ill Patients
Blood glucose meters that have been cleared by the FDA as waived for home use were originally designed as consumer devices, intended for use in monitoring glucose levels in an individual patient diagnosed with diabetes. Over time, the use of BGMS has expanded to include use in healthcare facilities for patient populations that manufacturer’s studies and performance standards did not address.
If manufacturer’s instructions contain limitations indicating that their BGMS has not been evaluated or cleared for use in critically ill patients, then use of BGMS on this patient population is considered “off-label” use. Off label use of BGMS changes their CLIA regulatory status to high-complexity testing.
For example, CMS described the use of a BGMS on a patient whose hematocrit or oxygenation level is below the range indicated in the manufacturer’s instructions as an off-label use. Results of blood glucose testing in this situation may be inaccurate and lead to clinical interventions that could cause patient harm.
Centers for Medicare and Medicaid Services sent a letter to state survey agency directors on November 21, 2014, addressing the off-label use of waived blood glucose monitoring systems (BGMS). CMS defined off-label use as using BGMS outside of its FDA approved intended use, limitations or precautions as stated in the manufacturer’s instructions. CLIA surveyor(s) have been instructed to whether a health care institution is using BGMS according to the manufacturer’s instructions or off-label.
Neither FDA nor CMS have defined critically ill patient populations. Therefore, each institution must define these in order to understand when use of glucose meters may be off-label and therefore high complexity.
Nova StatStrip glucose monitoring has received FDA approval for glucose measurement in intensively treated adult patients, though only with arterial and venous whole blood. So the real issue with this BGMS is the use of capillary blood sampling because it may lead to erroneous results in patients with poor tissue perfusion. Poor tissue perfusion occurs in patients with hypotension. Arterial hypotension is defined as systolic blood pressure below 90 mm Hg or mean arterial pressure below 60 mm Hg. For Nova StatStrip it seems logical to define a critically ill patient as a patient admitted to an intensive care unit with hypoperfusion defined on the basis of blood pressure readings. Capillary blood sampling would not be performed if a patient had systolic BP below 90 or MAP below 60.
