For a 3-day-old newborn (older than 48-72 hours), use plasma glucose <60 mg/dL (3.3 mmol/L) as the cutoff for hypoglycemia, particularly when screening for persistent hypoglycemia.

Confirm a low bedside glucometer result with a laboratory plasma glucose measurement. Symptomatic hypoglycemia, such as jitteriness, poor feeding, lethargy, apnea, or seizures, requires urgent treatment regardless of the exact value. The Pediatric Endocrine Society recommends a target glucose >60 mg/dL after 48 hours because ongoing hypoglycemia at this age may indicate an underlying disorder. PES recommendations