Special remarks:

The DEMEDITEC CA 19-9 RIA, an in vitro diagnostic test for the quantitative measurement of the CA 19‑9 tumor associated antigen, in human serum or plasma, is indicated for the serial measurement of CA 19-9 to aid in the management of patients diagnosed with cancers of the exocrine pancreas. The test is useful as an aid in:
Monitoring of disease status in those patients having confirmed pancreatic cancer who have levels of serum or plasma CA 19-9 above the cutoff, at the time of diagnosis.
CA 19-9 values must be interpreted in conjunction with all other available clinical and laboratory data before a medical decision is determined.

CA 19-9 assay levels are defined by using the 1116NS19-9 antibody to measure reactive determinants on a high molecular weight glycoprotein in serum or plasma. Initial clinical studies now confirmed world-wide, indicate that CA 19-9 assay levels are frequently elevated in the serum of patients with cancers of the pancreato-biliary system (PBS) (i.e. pancreas, gallbladder, biliary tract). In addition, elevated levels of CA 19-9 have been observed in other malignancies such as lung cancer, other gastrointestinal cancers and in some nonmalignant disorders.
Patients known to be genotypically negative for the Lewis blood group antigen will be unable to produce the CA 19-9 antigen even in the presence of malignant tissue. Phenotyping for the presence of the Lewis antigen may be insufficient to detect true Lewis antigen negative individuals. Even patients who are genotype positive for the Lewis antigen may produce varying levels of CA 19-9 based on gene dosage effect.