CA 19-9

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CA 19-9 antigen is a tumor marker used in diagnosing patients with pancreatic or hepatobiliary cancer. It is also useful in evaluating response to treatment and surveillance. [1], [2]


  • CA 19-9 is a carbohydrate cell-surface antigen that exists on the surface of cancer cells.
  • The presence of a pancreatic mass or biliary obstruction, along with greatly elevated CA 19-9 levels supports the diagnosis of pancreatic cancer
  • CA 19-9 is not generally used as a screening test for pancreatic or hepatobiliary tumors due to its lack of sensitivity and specificity.

Patient Preparation

  • No fasting required.
  • Factors which can cause increased levels
  • None noted
  • Factors which can cause decreased levels
  • None noted

Clinical Implications

High levels indicate: Pancreatic carcinoma

  • Hepatobiliary carcinoma
  • Pancreatitis
  • Cholecystitis
  • Cirrhosis
  • Gastric cancer
  • Colorectal cancer
  • Gallstones
  • Lung cancer

Low levels indicate:

Associated Tests

  • Carcinoembryonic antigen (CEA)


  1. Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.
  2. Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain.