Introduction: CA19-9 is a marker used in the diagnosis and monitoring of several cancer diseases. The aim of this study is to evaluate the CA19-9 assay on the Abbott ALinity Ci automated system. This evaluation is part of an overall approach to verifying the methods used in the CHU's central laboratory, with a view to compiling an accreditation file in line with the requirements of standard NF EN ISO 15189. Materials and methods: The aim of our study was to evaluate the scope A criteria detailed in the guide to verification/validation of methods in Medical Biology, in accordance with the recommendations of standards NF EN ISO/CEI 17025, NF EN ISO 15189 and NF EN ISO 22870. Verification was carried out on the CA19-9 assay on Alinity® Ci, which uses the immunoassay technique Criteria (repeatability, reproducibility) were verified. Results: The results obtained show good repeatability for the 3 levels with respectively CV1=2,61% , CV2=2,78% , and CV3 =3,26% % and intra-laboratory reproducibility with CV1=3,98% , CV2= 3,16% and CV3 = 3,61%. Discussion and Conclusion: The central laboratory of our University Hospital is committed to a quality policy which includes a control approach for the various analytical systems used. The results obtained for the various CA19-9 assay verification criteria on our Alinity® Ci system, compared with data from the supplier, RICOS and learned societies, are satisfactory and verify analytical performance.