ObjectiveTo systematically review the accuracy of T-cell receptor excision circles (TRECs) in screening newborns for severe combined immunodeficiency (SCID). MethodsThe PubMed, EMbase, Cochrane Library, Web of Science, CBM, WanFang Data and CNKI databases were electronically searched to collect the diagnostic accuracy studies related to the objects from inception to October 26, 2022. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies using the QUADAS-2 scale. Meta-analysis was performed using Stata 15.0 and Meta-Disc 1.4 software. ResultsA total of 18 studies involving 6 243 718 neonates were included. The results of meta-analysis showed that the pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnosis odds ratio (DOR) were 0.97 (95%CI 0.92 to 0.99), 1.00 (95%CI 1.00 to 1.00), 1447.05 (95%CI 528.49 to 3962.11), 0.13 (95%CI 0.08 to 0.22) and 11698.21 (95%CI 2853.44 to 47958.98), respectively. The area under the summary receiver operating characteristic curve (SROC) was 0.97. ConclusionThe application of TRECs in screening neonatal SCID has high accuracy, which is helpful for early diagnosis of SCID. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.