TABLE 1.

Critical sample during diagnostic fast

Parameter	Value in critical sample	Expected value in the setting of hypoglycemia	Diagnostic value for hyperinsulinism
Glucose (mg/dl)	48	<50	<50
Bethydroxybutyrate (mmol/L)	1.2	≥2	<1.8a
Free fatty acids (mmol/L)	0.8	≥1.7	<1.7
Insulin (uU/ml)	Undetectable	Undetectable	Above the level of detection
C-peptide (ng/ml)	0.4	<0.5	≥0.5
IGFBP-1 (ng/ml)	106	>110	≤110
Growth hormone (ng/ml)	N/A	≥7	N/A
Cortisol (mcg/dl)	7.1	≥10	N/A

Note: Reference: Ferrara, Patel, Becker, et al. (2015).

^a100% sensitivity and specificity.