Newborn Screening for Congenital Hypothyroidism-Clinical Evaluation and Comparison of Two Different Test Kits for the Determination of TSH in Dried Blood Samples on Two Different Platforms

Abstract

Newborn screening (NBS) for congenital hypothyroidism (CH) started in the 1970s, with the introduction of radioimmuno assays (RIA) for the measurement of thyroxine (T4), and thyroid stimulating hormone (TSH). With the development of sensitive enzyme immune assays (EIA, FIA, FEIA), RIAs were replaced in the newborn screening laboratories. With the increasing number of analytes and centralization of NBS, there is a growing demand of total automation. In the course of method validation, two fully automated platforms for the determination of TSH in dried blood samples (DBS) were compared. The GSP from PerkinElmer (PE), and the NS2400 from Labsystems (LDx), together with the recommended test kits from both manufacturers. Both systems showed good performance, with recoveries, of 103.0% (LDx) and 98.5% (PE), and CVs for intra and interassay variations at various concentrations, between 4.3 and 15.7. Both assays had a good correlation (r2 = 0.8814). With LDx/NS2400 platform, TSH values were in the mean 2.09 mU/L higher; however, the difference of both results from the mean was within ±2 SD, up to 30 mU/L, and only for values above 50 mU/L did the difference become bigger. However, this has no influence on the clinical interpretation. No false negative results were observed with either of the two platforms. TSH results obtained with the LDx/NS2400 were slightly higher than those obtained with the PE/GSP; however, the recall rate was lower: 0.059% compared to 0.063%. This can be explained by the much narrower distribution of TSH values. In conclusion, both platforms are equally suitable for medium and large NBS laboratories. However, due to the more open structure the LDx/NS2400 platform has a lot of advantages compared to the totally closed PE/GSP platform.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020–2023)

“…Other recent NBS activities have focused on laboratory testing: a report reviewing increased laboratory efficiency using a commercial robotic DBS extraction device in combination with LC-MS/MS [ 1047 ], a study to define reference intervals for total thyroxine (tT 4 ) in NBS specimens with emphasis on premature and term-born infants [ 1048 ], and a clinical comparison and evaluation of two commercial testing platforms for NBS for TSH in DBS [ 1049 ]. A recent Swiss study sought to describe the IRT levels in healthy newborns in their first year of life and by gestational age, and to compare IRT values at two time points in healthy newborns and newborns with CF [ 1050 ].…”

An Insight into Indonesia’s Challenges in Implementing Newborn Screening Programs and Their Future Implications

“…For example, although dried blood spot collections are preferable after 72 h, professional advocacy groups may release a national guideline on circumventing this problem. Another example will be the harmonization of cut-off levels, as different countries in the same nation may have different machines, policies, and standards [56].…”