II. Pathophysiology

  1. Cancer Antigen 19-9 is expressed in pancreatic disease and hepatobiliary disease
  2. CA 19-9 is a soluble, fucosylated glycosphingolipid CarbohydrateAntigen
  3. Structurally related to the Lewis Blood Group Antigens

III. Indications

  1. Pancreatic ductal adenocarcinoma
    1. Confirms diagnosis when consistent with other findings (see other False Positive causes below)
    2. Predicts prognosis as well as recurrence risk
      1. CA 19-9 level reduction by at least 50% after treatment is associated with a better prognosis
      2. Ye (2020) Cancer Chemother Pharmacol 86(6):731-40 +PMID: 33047181 [PubMed]
  2. Not indicated for screening in asymptomatic patients
    1. No tumor specific (see efficacy below)

IV. Causes: Increased CA 19-9

  1. Pancreatic Ductal Adenocarcinoma
  2. Chronic Pancreatitis
  3. Non-cancerous bile tract disease
  4. Chronic inflammatory states

V. Causes: False Negative

  1. False Negatives in 10% of population that fails to synthesize CA 19-9

VI. Efficacy: Pancreatic Ductal Adenocarcinoma Diagnosis

  1. CA 19-9 Level >37 U/ml
    1. Test Sensitivity: 72% (some studies have shown test sensitivities as low as 50%)
    2. Test Specificity: 86%
    3. Negative Likelihood Ratio (LR-): 0.32
    4. Positive Likelihood Ratio (LR+): 5.1
  2. High False Positive Rate in asymptomatic patients (do not use for screening)
    1. Kim (2004) J Gastroenterol Hepatol 19(2): 182-6 [PubMed]

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Related Studies

Ontology: CA-19-9 Antigen (C0006613)

Definition (NCI) CA 19-9 is a fucosylated glycosphingolipid carbohydrate antigen that is soluble and is adsorbed to erythrocytes and to many adenocarcinomas of the digestive tract, especially pancreatic tumors. By structure CA 19-9 is related to the Lewis blood group antigens.
Definition (MSH) Sialylated Lewis blood group carbohydrate antigen found in many adenocarcinomas of the digestive tract, especially pancreatic tumors.
Concepts Carbohydrate (T118) , Immunologic Factor (T129)
MSH D018395
SnomedCT 103086009
LNC LP14040-7, MTHU008551
English Antigen, CA-19-9, Antigen, Gastrointestinal Cancer, CA-19-9 Antigen, Cancer Antigen, Gastrointestinal, Gastrointestinal Cancer Antigen, Antigen CA 19 9, Antigen CA-19-9, Antigen, CA 19-9, Antigen, CA 19.9, CA 19-9 Antigen, CA 19.9 Antigen, CA-19-9, Antigen, CA19.9 - Carbohydrate antigen 19.9, CA19.9-Carbohydrat antign 19.9, ANTIGEN CA 019 009, CA ANTIGEN 019 009, CA-19-9 Antigen [Chemical/Ingredient], ca19-9, ca-19-9, ca 19 9, ca19 9, cancer antigen 19-9, carbohydrate antigen 19-9, CA 19 9 Antigen, SLeA, Sialylated Lewis (a) Antigen, Sialylated Lewis a Antigen, Sialyl LeA, Sialyl Le(a) Antigen, Sialyl LewisA, Cancer Ag 19-9, Cancer antigen 19-9, Carbohydrate antigen 19.9, CA 19.9 - Carbohydrate antigen 19.9, Cancer antigen 19-9 (substance), Cancer Antigen 19-9, Carbohydrate Antigen 19-9, CA-19-9, CA19-9 Antigen, CA19-9
Swedish CA-19-9-antigen
Czech CA-19-9 Antigen
Finnish CA-19-9-antigeeni
Russian ANTIGEN OPUKHOLEASSOTSIIROVANNYI 19-9, CA-19-9 ANTIGEN, ZHELUDOCHNO-KISHECHNOGO NOVOOBRAZOVANIIA ANTIGEN, CA-19-9 АНТИГЕН, АНТИГЕН ОПУХОЛЕАССОЦИИРОВАННЫЙ 19-9, ЖЕЛУДОЧНО-КИШЕЧНОГО НОВООБРАЗОВАНИЯ АНТИГЕН
Japanese CA-19-9抗原, CA19-9抗原, 胃腸癌抗原, 抗原-CA-19-9
French Antigène CA-19-9, Antigène CA 19-9, Antigène du cancer gastro-intestinal
German CA ANTIGEN 019 009, ANTIGEN CA 019 009, Antigen CA-19-9, CA-19-9-Antigen, Gastrointestinales Krebsantigen
Spanish antígeno asociado a carcinoma 19-9, antígeno cancerígeno 19 - 9 (sustancia), antígeno carbohidrato 19-9, antígeno cancerígeno 19 - 9, antígeno asociado a carcinoma 19-9 (sustancia), CA 19-9 - antígeno carbohidrato, Antígeno CA-19-9, Antígeno de Cáncer Gastrointestinal
Polish Antygen CA-19-9
Portuguese Antígeno CA-19-9, Antígeno de Câncer Gastrointestinal
Italian Antigene CA-19-9