CA 19-9 (Pancreatic Cancer Marker)
CA 19-9 is a tumor marker blood test used to monitor pancreatic cancer and other digestive tract cancers. It helps track treatment response and cancer progression.
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What this test measures
The CA 19-9 test measures the amount of a protein called CA 19-9 (cancer antigen 19-9) in a sample of blood. CA 19-9 is a type of tumor marker, which are substances made by cancer cells or by normal cells in response to cancer. Carbohydrate antigen (CA) 19-9 is a type of antigen released by pancreatic cancer cells and can also be referred to as a tumor marker. The test is commonly used in individuals with known or suspected pancreatic cancer to monitor the progression of the disease and response to treatment.
High levels of CA 19-9 can be a sign of certain cancers of the digestive tract, including cancers of the colon and rectum. However, pancreatic cancer is merely one of several conditions that may cause elevated levels of CA 19-9. Increased levels can be seen in healthy individuals, in benign conditions, and in other malignant conditions, particularly cholestasis and jaundice, such as from bile duct disease, cirrhosis, or pancreatitis. Because high levels of CA 19-9 can mean different things, healthcare providers don't use the results from a CA 19-9 test alone to screen for or diagnose cancer or other diseases.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals who have been diagnosed with pancreatic cancer and need to monitor their treatment response and disease progression, as CA 19-9 levels can help healthcare providers assess whether treatment is working effectively.
- Patients who have completed pancreatic cancer treatment and require ongoing surveillance to detect potential cancer recurrence, as rising CA 19-9 levels may indicate the cancer has returned.
- Those with suspected pancreatic cancer who are undergoing additional diagnostic testing, where CA 19-9 levels may provide supporting information when combined with imaging studies and other diagnostic procedures.
- People with other digestive tract cancers such as bile duct cancer (cholangiocarcinoma), colorectal cancer, or gallbladder cancer, where elevated CA 19-9 levels may assist in monitoring disease status.
- Individuals at high risk for pancreatic cancer due to family history or genetic predisposition who may benefit from periodic monitoring as part of a comprehensive surveillance plan recommended by their healthcare provider.
What to expect
Preparation
No fasting is required for the CA 19-9 test. Patients should inform their healthcare provider about any medications or supplements they are taking, as some may potentially affect results.
Sample Type
A simple blood draw from a vein in the arm using a small needle. The procedure typically takes just a few minutes and may involve a brief pinch when the needle is inserted.
Collection
At the lab location, a healthcare professional will clean the area, insert a small needle to collect the blood sample, and apply a bandage. The sample is then labeled and sent to the laboratory for analysis.
Turnaround
Results are typically available within 1-2 business days after the sample reaches the laboratory, with no doctor visit required to receive your confidential test results.
Understanding your results
The reference range of serum CA 19-9 is less than 37 U/mL, with the normal CA 19-9 range in a healthy person being 0-37 units per milliliter. Healthcare providers don't use the results from a CA 19-9 test alone to screen for or diagnose cancer or other diseases because high levels of CA 19-9 can mean different things. Results must be interpreted by a healthcare provider within the context of the individual's medical history, physical examination, and other diagnostic tests.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 0-37 U/mL | Normal reference range for healthy individuals; levels above this range may warrant further evaluation |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
CA 19-9 levels in the normal range (0-37 U/mL) typically suggest the absence of significant tumor activity, though this must be interpreted carefully. Approximately 5% of the population is unable to produce the CA 19-9 antigen, and about 6% of the white population and 22% of the black population in the United States are Lewis antigen-negative and do not generate the specific sialyl antigen, which will result in falsely negative CA 19-9 levels even in the presence of pancreatic cancer. Low or normal CA 19-9 levels do not definitively rule out pancreatic cancer or other malignancies, particularly in early-stage disease. Healthcare providers may recommend additional testing or monitoring even with normal CA 19-9 levels if other clinical factors suggest the possibility of cancer.
What does a “High” result mean?
CA 19-9 levels above 37 U/mL may indicate cancer, though it's also possible to have a benign condition that causes CA 19-9 levels to rise. Sometimes a person will fall in the normal range for CA 19-9 even if they have a type of cancer that usually produces it. A high CA 19-9 is usually related to pancreatic cancer, but other cancers like colorectal, lung and gallbladder cancers can also cause raised levels. Elevated levels may also be caused by non-cancerous conditions including pancreatitis, bile duct disease, liver disease, gallstones, or cystic fibrosis. Healthcare providers typically order additional tests and imaging studies to determine the underlying cause of elevated levels. When CA 19-9 levels are greater than 1000 U/mL, the positive predictive value and specificity approach 100% and are correlated with unresectable tumors. However, even significantly elevated levels require comprehensive evaluation by healthcare professionals to determine the specific cause and appropriate next steps.
Privacy & confidentiality
All CA 19-9 test results are strictly confidential and protected under HIPAA regulations. Results are not sent to your personal doctor unless you specifically request it, will not be added to your medical records, and will not appear on insurance EOB statements since no doctor visit is required for testing.
Frequently asked questions
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This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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