A Small‐Scale Regional External Quality Assessment of Nucleic Acid Amplification Tests for <scp> <i>Bordetella pertussis</i> </scp> in China

ABSTRACT Background Bordetella pertussis (BP) infection remains a major public health concern because of its substantial clinical and epidemiological impact. Although nucleic acid amplification tests (NAATs) are widely used for pertussis diagnosis, their real‐world performance in routine clinical laboratories has not been systematically evaluated. This study implemented an external quality assessment (EQA) program to assess laboratory proficiency and identify potential sources of analytical variability. Methods An EQA panel comprising five samples (four positive and one negative) was prepared using 10‐fold serial dilutions of BP (2.0 × 10 2 –2.0 × 10 5 copies/mL). The panel was distributed to participating laboratories, and performance was evaluated based on qualitative agreement with the expected results. Results A total of 69 laboratories participated, including 63 (91.30%) hospital‐based laboratories and 6 (8.70%) independent clinical laboratories, generating 345 test results. All laboratories achieved acceptable performance (scores ≥ 80). The overall concordance rate was 98.84% (341/345). Four false‐negative results were identified, all of which occurred in the lowest‐concentration sample (200 copies/mL). Conclusion Pertussis NAATs demonstrated generally reliable diagnostic performance among participating laboratories in Chongqing, China. However, challenges remain in detecting low‐copy‐number specimens near the analytical sensitivity threshold. Continuous quality monitoring, standardized workflows, optimized nucleic acid extraction procedures, and regular performance verification are essential to ensure accurate pertussis diagnosis and support effective public health surveillance and outbreak response.