Abstract:

Objective To establish the reference range of carbohydrate antigen 50 （CA50 ）for adults in Shanghai by indirect method （Hoffmann method） and verify its applicability. Methods The 46 764 cases of original CA50 determination data in the laboratory information management system of Zhongshan Hospital of Fudan University from August 2022 to July 2023 were collected for the establishment of CA50 reference range. Totally，691 healthy subjects at Zhongshan Hospital of Fudan University from January to March 2024 were enrolled for the verification of the self-established reference range. The individuals from the physical examination population of Zhongshan Hospital of Fudan University from August 2022 to March 2024 with CA50≥25 U·mL^-1（current reference range）but lower than the self-established reference range were selected to verify the applicability of the self-established reference range. Turkey method was used to eliminate outliers. Z test was used to compare whether there were differences in CA50 levels among different genders and ages. The 95% reference range of serum CA50 was established using the Hoffmann method. Results Totally，17 773 valid data were obtained. The Z test results showed that there was statistical significance in CA50 levels among different genders and ages（Z value > Z* value）. The 95% reference ranges of CA50 were established for different genders and ages using the Hoffmann method. That for male individuals aged 18-59 years was <27.30 U·mL^-1，and that for female individuals was <29.62 U·mL^-1. That for male aged ≥60 years was <36.85 U·mL^-1，and that for female individuals was <34.85 U·mL^-1. The CA50 levels of 691 healthy individuals were within the self-established reference range，and the reference range verification was successful. Among the 191 individuals with CA50≥25 U·mL^-1（current reference range）and lower than the self-established reference range，38（19.90%）individuals had abnormal liver function，renal function，B-ultrasound or computed tomography（CT）results，while the other 153 （80.10%） individuals had normal examination results. Conclusions The Hoffmann method has established the reference range of CA50 for adults in Shanghai by gender and age，which is different from the current reference range and is more applicable in clinical practice.

Key words: Carbohydrate antigen 50, Indirect method, Reference range