Newborn Screening Tests

Blood and hearing tests performed in hospital within first days of life to detect treatable conditions before symptoms appear.

Blood Screening

Tests for metabolic and genetic disorders that require immediate dietary or medical management. Number of conditions screened varies significantly by location—California tests for 61 disorders, other states fewer.

Common conditions detected:

• Phenylketonuria (PKU) — 1 in 10,000 births. Inability to break down phenylalanine amino acid. Requires low-protein diet from birth to prevent severe intellectual disability and death.
• Metabolic disorders — Inability to digest specific proteins or produce essential enzymes
• Hormone deficiencies — Thyroid and adrenal conditions

Sample collection: Single heel prick, blood collected on filter paper card.

Results: No news typically means normal results. Abnormal results trigger immediate follow-up testing and specialist referral.

Hearing Test

Detects hearing loss in 1–3 per 1,000 infants. Early detection enables intervention (hearing aids, implants) before language development critical period.

Method: Sensors on head or ear probes detect middle/inner ear response to tones. Baby can be asleep during test.

Accuracy:

• Detection rate: 85–100% of hearing loss cases
• False positive rate: ~4% (fail initial screening but have normal hearing)

Follow-up: Failed test generates referral to audiological centre for comprehensive evaluation. High false positive rate means most infants who fail initial screen have normal hearing.

Why Immediate Testing Matters

Many screened conditions cause irreversible damage within days or weeks if untreated. PKU, for example, causes brain damage from protein in breast milk/formula before symptoms would be noticed. Early detection enables dietary modifications that prevent all negative outcomes.

See also: Hospital Procedures After Birth, [[Jaundice in Newborns]], [[Vitamin K Injection]], Paediatric Follow-Up Schedule