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CA 19-9

CA 19-9 — tumor marker used for treatment monitoring in pancreatic and biliary tract cancers.

Blood tumor marker used to monitor treatment response and recurrence in pancreatic and biliary tract cancers. Not used for screening.

Indication

  • Monitoring treatment response in diagnosed pancreatic cancer
  • Follow-up of biliary tract cancer (cholangiocarcinoma)
  • Monitoring recurrence after surgery
  • Assessment of treatment efficacy during chemotherapy
  • Supportive test in differential diagnosis of pancreatic mass (together with clinical findings)
  • Routine follow-up in patients responding to treatment

Preparation

  • Special fasting is not required; however, 8-12 hours of fasting may be advised when ordered with combined tests
  • Current medications and history of jaundice should be reported
  • Bringing previous tumor marker results

How it's performed

  1. A venous blood sample is drawn from the arm
  2. Serum is separated and measurement is performed by immunological method
  3. Result is reported in U/mL; threshold values vary by laboratory
  4. Interpretation is performed together with clinical findings and imaging

Post-procedure

  • Repeat measurement at defined intervals during the treatment process
  • Rising values are evaluated with imaging
  • Results are discussed in person with the physician
  • Awareness that values may be falsely elevated in jaundice (biliary obstruction)

Risks

  • Minor bruising or tenderness related to blood draw
  • False elevation in benign conditions such as jaundice, pancreatitis, and cholangitis
  • In Lewis antigen-negative individuals (~5-10%), test results may be unreliable
  • Use as a screening test may lead to erroneous results

FAQ

If CA 19-9 is high, does it definitely mean cancer?

No. It can also rise in benign conditions such as pancreatitis, jaundice, cholangitis, and liver diseases. It does not establish a diagnosis on its own.

Can I have it done for pancreatic cancer screening?

CA 19-9 is not recommended as a screening test. It is used only in patients with a confirmed diagnosis for treatment monitoring and recurrence follow-up.

When are the results available?

Most laboratories provide results the same day or within 1 business day.