What is the red flag hypoglycemia threshold in newborns?

• A. <40 mg/dL
• B. <60 mg/dL
• C. <30 mg/dL
• D. <50 mg/dL

Answer: (A)

Newborns regulate glucose poorly, so a drop in blood sugar can quickly affect the brain. The red flag threshold used to signal urgent action is 40 mg/dL. When glucose falls to or below this level, clinicians escalate care promptly to raise the blood sugar and prevent neuroglycopenia, because brain injury can occur if hypoglycemia is not corrected.

In practice, assess the infant for symptoms such as jitteriness, poor feeding, lethargy, or seizures, and treat accordingly. If the baby is feeding well, an oral/feed-based approach may be attempted to raise glucose; if not, or if symptoms are present, more definitive treatment like IV dextrose is indicated per protocol.

The other values are not the standard red-flag threshold: they represent higher or lower cutoffs used in different contexts and do not prompt the same immediate urgency as 40 mg/dL.