Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1026 page)

   
Normal range:
fasting molar ratio insulin to C-peptide = 1.0.

   Use

   To differentiate insulinoma from factitious hypoglycemia due to insulin

   Interpretation

   
Less than 1.0 in molarity units (or
>
47.17
μ
g/ng in conventional units)

   Increased endogenous insulin secretion (e.g., insulinoma, sulfonylurea administration)

   Renal failure

   
Greater than 1.0 in molarity units (or <47.17
μ
g/ng in conventional units)

   Exogenous insulin administration

   Cirrhosis

   Limitations

   There are ethnic differences in insulin/C-peptide ratio in both fasting and glucose-stimulated conditions in normal young nondiabetic pregnant women. Compared with their Caucasian and Hispanic counterparts, African American women had indices suggestive of lower insulin production and greater insulin resistance (i.e., a lower C-peptide concentration, a lower C/I ratio, and elevations in insulin and the I/G ratio).

INTRINSIC FACTOR ANTIBODY

   Definition