When is repeat newborn screening recommended?

When to Repeat Newborn Screening

Repeat newborn screening is recommended for infants who fail initial screening tests, with timing dependent on the specific condition being screened and risk factors present. 1, 2

Hearing Screening Follow-up

• Infants who fail the initial in-hospital hearing screening should be referred for repeat testing between 2 and 8 weeks after discharge 1, 2
• If an infant fails the second screening, they should be referred for comprehensive audiological evaluation including diagnostic Auditory Brainstem Response (ABR) testing or other electrophysiologic testing, which can be performed as early as 3 months of age 1, 2
• Visual reinforcement audiometry cannot be performed reliably before age 8 to 9 months, so earlier diagnostic methods are preferred 1

Metabolic and Genetic Disorder Screening

• For infants with borderline or abnormal metabolic screening results, prompt referral to a specialty care center is essential for comprehensive evaluation and definitive diagnosis 1, 3
• Relying solely on "metabolite diagnoses" or "gray-zone" results without confirmatory testing can lead to incorrect diagnoses and inappropriate clinical management 1, 3
• For conditions like cystic fibrosis using an IRT/DNA algorithm, infants with a positive screening test (elevated IRT and ≥1 detected mutation) should be referred to a diagnostic center for a sweat chloride test 1

Special Populations Requiring Repeat Screening

Preterm Infants

• Preterm infants should receive repeat screening for conditions such as congenital hypothyroidism at 36 weeks' gestational age or term-equivalent age 4, 5
• Studies show that repeating screening only at 2 weeks of life in preterm infants will miss approximately 48% of cases with delayed thyroid-stimulating hormone (TSH) elevation 5
• Some preterm infants with normal initial screening can develop significant hypothyroidism by term-equivalent age, highlighting the importance of repeat screening 4

High-Risk Infants

• Infants with risk factors for hearing loss should have ongoing developmentally appropriate hearing screening and at least one diagnostic audiology assessment by 24-30 months of age 2
• Infants who spent time in the NICU should be screened using ABR technology, as they are at higher risk for neural hearing loss 2
• For infants who fail ABR testing in the NICU, referral should be made directly to an audiologist rather than for general outpatient rescreening 2

Critical Congenital Heart Disease (CCHD) Screening

• For CCHD screening, the American Academy of Pediatrics recommends only one retest following an indeterminate result, rather than two retests as previously recommended 1
• This change shortens the time to recognition of CCHD and has minimal effect on false-positive rates 1

Common Pitfalls in Newborn Screening Follow-up

• Loss to follow-up is a significant challenge - studies show that 13% to 31% of infants who fail initial screening do not return for follow-up testing 1, 2
• False-positive results can produce significant anxiety in 3% to 14% of parents, even after follow-up testing 1, 2
• Treating borderline results as definitively diagnostic without confirmatory testing should be avoided 1, 3
• Failing to refer to appropriate specialists can lead to delayed diagnosis and treatment 2, 3

Benefits of Proper Follow-up

• Universal newborn screening has reduced the mean age of identification of hearing impairment from 12-13 months to 3-6 months 1, 2
• Early identification allows for earlier intervention, with the mean age for hearing aid fitting reduced from 13-16 months to 5-7 months 1, 2
• Comprehensive evaluation that ends with a definitive diagnosis is warranted for each infant with abnormal screening results 1
• Correctly determining a diagnosis is crucial for appropriate treatment, follow-up, and refinement of screening programs 1