CA 19-9 (Tumour marker)
Chemical Pathology
Notes
As with most tumour markers there is a high incidence of false positive and false negative results. CA 19-9 is most appropriately used in monitoring disease progression or effectiveness of treatment once diagnosis of the tumour has been made and serum concentrations have been shown to be raised prior to treatment (Lewis negative individuals do not express CA 19-9).
CA 19-9 has been shown to be raised in:
- Pancreatic adenoncarcinomas (most)
- Gastric carcinomas (50%)
- Colorectal carcinomas (30%)
CA 19-9 should not be used for non-GIT malignancy.
Sample requirements
If patient on high dose biotin therapy (>5mg/day) collect sample at least 8 hours after the last dose.
For adults, 5 ml of blood taken into a narrow gold top tube (or rust top for the Acute Unit)
Storage/transport
Send at ambient temperature to the laboratory. If unavoidable, samples can be stored refrigerated overnight.
Required information
Relevant clinical details, including site of primary tumour. Is the test being used for baseline levels prior to treatment or for follow-up?
Turnaround times
The assays are run on a daily basis Monday to Friday.
The in-lab turnaround time is less than 4 days.
Reference ranges
Assayed using the Cobas CA 19-9 ECLIA
Reference range: less than 34 kU/L
Further information
Lab Tests Online: CA 19-9 Test
Monograph of the Association for Clinical Biochemistry and Laboratory Medicine
BMJ 2009; 339: b3527 Serum tumour markers: how to order and interpret them
Page last updated 20/09/2017