Produced in equimolar amounts to insulin but not cleared by the liver. Distinguishes endogenous insulin secretion from exogenous insulin administration.
| Sex | Age | Range | Notes |
|---|---|---|---|
| All | ≥ 18 yrs | 0.37 – 1.47 | Adult fasting; stimulated peak >0.6 nmol/L supports residual β-cell function |
⚠ Clinical Note
Reference ranges are indicative. Always interpret results in the context of the individual patient and local laboratory reference intervals, which may vary.