Definition of Critically Ill Patients

Capillary whole blood specimens (fingerstick) should NOT be used in "critically ill"patients receiving intensive medical intervention/therapy because of the potential for pre-analytical collection error and specifically in patients with decreased peripheral blood flow, as it may not truly reflect the patient's true physiological state. These include, but are not limited to, severe dehydration, severe hypotension, shock and hyperglycemic-hyperosmolar state with or without ketosis.
"Critically ill" is any illness or injury that acutely impairs one or more vital organ systems such that there is a high probability of imminent or life threatening deterioration in the patient's condition and requires continuous bedside attendance of a physician or advanced practice clinician for 30 minutes or longer. Venipunctures should be performed on these patients.

I attended a webinar by James Nichols from Vanderbilt. The way I understand it, they classify critically ill patients as those that fall within the limitation parameters on the device's package insert/manual.

Our facility's definition of critically-ill for blood glucose monitoring is any patient with a mean arterial pressure <60mmHg despite the use of vasopressors.  We also teach to not use a capillary sample from any patient with peripheral flow issues.

Here is the statement in our procedure for the Nova meter:

ICU admissions and patients in the ICU or in the OR with one or more of the following:

1. Hct >50

2. Significant capillary bed fluid balance problems including significant dehydration or severe edema

3. Receiving inotropic and/or vasopressor agents

Summarizing, if an adult patient meets this definition of "critically ill", capillary blood testing for glucose must not be performed; rather a venous or arterial sample should be used.