Chemistry, toxicology & urinalysis

• Refers to a group of tests performed on newborns to identify early presymptomatic, treatable disorders, for which timely intervention is critical to improve long term outcome
• Intended to identify clinically occult but potentially serious disorders that require immediate intervention
• Considered a great public health achievement
  • It is a state mandated public health program that begins with a heel poke for every baby before hospital discharge
  • Parents have a right to opt out of NBS testing; each state has a procedure for the opt out process
  • NBS is not a diagnostic test; it identifies babies at increased risk for certain genetic, metabolic or functional diseases
• The 6 pillars for a successful NBS program include education, testing, follow up, diagnosis, intervention or management, and evaluation (Mol Genet Metab 2001;74:64)
• The NBS program in the United States includes screening for
  • Hearing loss
  • Critical congenital heart defects (CCHD)
  • Dried blood spot screening
    • Testing for metabolic, hematologic, endocrine and other inheritable disorders
    • Disorders included in the NBS panel are ones that can cause significant morbidity, mortality or intellectual disability without intervention
• Reference: Birth Defects Res 2020;112:350

Which of the following statements is true about the newborn screening program?

1. The best time to collect heel prick blood spots from babies is immediately after birth
2. Detects all inborn errors of metabolism
3. It includes dried blood spot screening, hearing loss screening and congenital heart disease screening
4. It is a federally mandated program in the United States
5. It is estimated that ~20% of initial newborn screen results are false positives

C. It includes dried blood spot screening, hearing loss screening and congenital heart disease screening. Answer D is incorrect because newborn screening is a state mandated program in the United States. Answer B is incorrect because it does not detect all inborn errors of metabolism. Answer A is incorrect because blood spots should be collected between 24 - 48 hours of birth after feeding has been established. Answer E is incorrect because false positives account for ~90% of cases; each positive result must be confirmed as soon as possible.

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Reference: Newborn screening

Which of the following is necessary for addition of a new disorder to the recommended universal screening panel (RUSP) for newborn screening?

1. Disorders added to RUSP must be supported by patient advocacy groups
2. Availability of a screening test with appropriate sensitivity and specificity
3. The disorder has to be clinically present in the newborn period
4. There must be a federal law passed mandating the addition of the disorder to the RUSP
5. The screening test must be approved by the United States Food and Drug Administration (FDA)

B. Availability of a screening test with appropriate sensitivity and specificity. This is one of the criteria for adding a disorder to the recommended universal screening panel (RUSP). Answer D is incorrect because no federal law is required for addition of disorders; the RUSP is a guide to states for newborn screening (NBS). Answer C is incorrect because the disorder does not have to present clinically in the newborn period. Answer A is incorrect because there is no requirement that disorders added to RUSP must be supported by patient advocacy groups. Answer E is incorrect because the screening test does not have to be FDA approved.

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Reference: Newborn screening