Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (962 page)

   Other

   Exogenous insulin (factitious)

   Oral hypoglycemic medications (factitious)

   Leucine sensitivity

   Malnutrition

   Hypothalamic lesions

   Alcoholism

   Limitations

   Most glucose strips and meters quantify whole blood glucose, whereas most laboratories use plasma or serum, which reads 10–15% higher.

   In whole blood glucose determinations, hematocrit of >55% causes decreased result. Hematocrit of <35% causes increased result.

   Blood samples in which serum is not separated from blood cells show glucose values decreasing at rate of 3–5% per hour at room temperature.

   Postprandial capillary glucose is ≤36 mg/dL higher than venous glucose at peak of 1 hour postprandial; usually returns to negligible fasting difference within 4 hours, but in approximately 15% of patients, there may still be >20 mg/dL difference.

   Low oxygen content (e.g., venous blood, high altitudes >3,000 m) gives falsely increased values.