When should newborn screening be performed?

When should newborn screening be performed?

• A. After 24 hours of life, not later than 3 days
• B. Before birth
• C. Within the first hour after birth
• D. After one week

Answer: (A)

Newborn screening relies on detecting biomarkers that rise to detectable levels after the baby has started life chemistry, while also catching conditions early enough to intervene. If done too soon, maternal hormones and immature metabolic systems can mask abnormalities, increasing false negatives. If done too late, treatment is delayed and outcomes can worsen. The best window is after 24 hours of life but before about 3 days, which balances reliable detection with timely intervention. Options that propose screening before birth, in the first hour, or after a week do not fit this balance.

Newborn screening relies on detecting biomarkers that rise to detectable levels after the baby has started life chemistry, while also catching conditions early enough to intervene. If done too soon, maternal hormones and immature metabolic systems can mask abnormalities, increasing false negatives. If done too late, treatment is delayed and outcomes can worsen. The best window is after 24 hours of life but before about 3 days, which balances reliable detection with timely intervention. Options that propose screening before birth, in the first hour, or after a week do not fit this balance.