Carbohydrate Antigen 19-9
CA19-9 is used as a tumour marker in pancreatic, colorectal and
biliary tract tumours. Serum CA19-9 is grossly raised in ~80% of
stage 2 pancreatic carcinoma (may also be raised in chronic
pancreatitis but rarely >60 kU/L). However, elevated
levels are also found in hepatobiliary disease associated with
cholestasis (may be >9,000 kU/L).
Request on ICE
Analysed by referral laboratory if specific criteria met.
Monitoring of known pancreatic and gastrointestinal
NOTE: If a patient is having serial tumour marker levels
monitored the tests must all be done at the same laboratory as
there are significant variations between assays
Sent to referral laboratory (Charing Cross)
Causes for Rejection
Unlabelled or incorrectly labelled sample; not meeting specific
criteria for analysis
Less than 33 kU/L
Half-life in Serum
Approx. 1 day but can vary from less than 1 day to 3 days.
CA19-9 levels are elevated in most pancreatic adenocarcinomas,
~50% of gastric carcinomas and ~30% of colorectal carcinomas.
Levels may also be elevated in benign conditions: acute and chronic
pancreatitis, hepatocellular jaundice, cirrhosis, acute cholangitis
and cystic fibrosis.
CA19-9 is excreted in bile and levels should be interpreted with
caution in cholestasis.
Approximately 5% of the population cannot express this antigen
(Lewis a-b-) so the test cannot be used to screen for an unknown