This kit is used for quantitative detection of CA15-3 in human serum in vitro. CA15-3 is a kind of glycoprotein with molecular weight of about 400kd. The detection of serum CA15-3 is mainly used for the monitoring and screening of breast cancer. CA15-3 is a useful tumor marker to evaluate the prognosis of patients. If the serum CA15-3 value does not return to normal after operation, it indicates that there are still residual tumors, and the recurrence of tumor is usually accompanied by the increase of serum CA15-3 before the occurrence of obvious clinical symptoms. CA15-3 is generally considered as a marker of breast cancer.