Newborn screening and the screening laboratory: past, present and future

Area of Science:

• Endocrinology
• Neonatal Screening
• Developmental Biology

Background:

• Thyroid hormone (TH) is vital for fetal and neonatal brain development.
• TH deficiency during early life can cause irreversible neurological deficits.
• Congenital hypothyroidism (CH) is a treatable condition if detected early.

Purpose of the Study:

• To review the laboratory evolution of newborn screening (NBS) for CH.
• To compare different screening markers and their historical implementation.
• To highlight the shift towards thyroid-stimulating hormone (TSH) in CH screening.

Main Methods:

• Historical review of CH screening methodologies since 1973.
• Analysis of the transition from thyroxine (T4) to TSH as primary screening markers.
• Discussion of laboratory techniques and their advancements in sensitivity.

Main Results:

• Early CH screening utilized total thyroxine (T4) measurements in dried blood spots.
• Increased sensitivity of TSH assays led to its widespread adoption as the primary NBS marker for CH.
• Some programs continue to use T4 to detect both primary and central CH.

Conclusions:

• Newborn screening for CH has evolved significantly, improving early detection rates.
• TSH is the predominant marker for CH screening globally due to assay sensitivity.
• Laboratory advancements are key to effective CH screening and prevention of developmental issues.