Introduction: Newborn screening (NBS) by quantifying T cell receptor excision circles
(TRECs) and Kappa receptor excision circles in neonatal dried blood spots (DBS) enables early diagnosis
of different types of primary immune deficiencies. Global newborn screening for PID, using an
assay to detect T-cell receptor excision circles (TREC) in dried blood spots (DBS), is now being performed
in all states in the United States. In this review, we discuss the development and outcomes of
TREC, TREC/KREC combines screening, and continued challenges to implementation.
Objective: To review the diagnostic performance of published articles for TREC and TREC/ KREC
based NBS for PID and its different types.
Methods: Different research resources were used to get an approach for the published data of
TREС and KREC based NBS for PID like PubMed, Scopus, Google Scholar, Research gate EMBASE.
We extracted TREC and KREC screening Publisher with years of publication, content and
cut-off values, and a number of retests, repeat DBS, and referrals from the different published pilot,
pilot cohort, Case series, and cohort studies.
Results: We included the results of TREC, combined TREC/KREC system based NBS screening
from different research articles, and divided these results between the Pilot studies, case series, and
cohort. For each of these studies, different parameter data are excluded from different articles. Thirteen
studies were included, re-confirming 89 known SCID cases in case series and reporting 53 new
SCID cases in 3.15 million newborns. Individual TREC contents in all SCID patients were <25
TRECs/μl (except in those evaluated with the New York State assay).
Conclusion: TREC and KREC sensitivity for typical SCID and other types of PID was 100 %. It
shows its importance and anticipating the significance of implementation in different undeveloped
and developed countries in the NBS program in upcoming years. Data adapting the screening algorithm
for pre-term/ill infants reduce the amount of false-positive test results.