Transitioning from Laboratory-Developed Tests to a Single Commercial Reagent Kit in a National Newborn Screening...

Area of Science:

• Biochemistry
• Clinical Diagnostics
• Public Health

Background:

• Newborn screening in England previously faced harmonization challenges due to diverse laboratory-developed tests (LDTs) and commercial assays for inherited metabolic disorders.
• The introduction of hereditary tyrosinemia type 1 screening necessitated modifications to LDTs, presenting an opportunity for standardization.

Purpose of the Study:

• To evaluate the analytical performance and harmonization achieved by implementing a single commercial reagent kit across all 13 newborn screening laboratories in England.
• To assess the impact of the commercial kit on inter-laboratory variation and standardization of screening for inherited metabolic disorders.

Main Methods:

• A verification study was conducted across 13 laboratories in England.
• A single commercial reagent kit was implemented for screening inherited metabolic disorders, including the measurement of succinylacetone.
• Instrument-specific correction factors were applied to analytical results.

Main Results:

• The commercial kit successfully reduced inter-laboratory variation for all measured analytes, demonstrating improved harmonization.
• Significant instrument-specific correction factors were required, indicating a lack of true standardization.
• Succinylacetone measurement was affected by instrument-dependent background interference, impacting performance.

Conclusions:

• While the commercial kit improved harmonization, the reliance on correction factors highlights ongoing standardization issues in newborn screening.
• Evidence-based screening cut-off values (COV) are crucial, rather than relying on published thresholds, due to instrument-specific interferences.
• Traceable reference materials and the analysis of screening outcome data are essential for enhancing laboratory quality and the effectiveness of newborn screening programs.