CA 19-9 exam: what it is, what it is for and results
CA 19-9 is a protein released by cells in some types of tumor, being used as a tumor marker. Thus, the CA 19-9 exam aims to identify the presence of this protein in the blood and assist the diagnosis of some types of cancer, especially pancreatic cancer in an advanced stage, in which the levels of this protein are quite high in the blood . Here's how to identify pancreatic cancer.
The types of cancer that are most easily identified with this test include:
- Pancreatic cancer;
- Colorectal cancer;
- Gallbladder cancer;
- Liver cancer.
However, the presence of CA 19-9 can also be a sign of other diseases such as pancreatitis, cystic fibrosis or obstruction of the bile ducts, for example, and there are even people who may have a slight increase in this protein without any problem.
When examination is required
This type of examination is usually ordered when symptoms appear that may indicate cancer in the gastrointestinal tract such as frequent nausea, swollen belly, weight loss, yellowish skin or abdominal pain. Usually, in addition to the CA 19-9 exam, others can also be done that help to specifically identify the type of cancer, such as the CEA exam, bilirubin and, sometimes, exams that evaluate the liver. See what are the liver function tests.
In addition, this test can be repeated even after a cancer diagnosis already exists, being used as a point of comparison to find out if the treatment is having any results on the tumor.
Check out the 12 signs that may indicate cancer and which tests are used.
How the exam is done
The CA 19-9 exam is done like a normal blood test, in which a blood sample is collected and sent to the laboratory for analysis. For this type of clinical analysis, no specific preparation is required.
How to interpret the results
The presence of low amounts of CA 19-9 protein is normal, even in healthy people, however, values above 37 U / mL generally indicate that some type of cancer is developing. After the first exam, the test can be repeated several times to check the effectiveness of the treatment, which may indicate:
- The result increases: it means that the treatment is not having the expected result and, therefore, the tumor is increasing, leading to a higher production of CA 19-9 in the blood;
- The result remains: it can indicate that the tumor is stable, that is, it does not grow or decrease, and it can indicate to the doctor the need to change the treatment;
- The result decreases: it is usually a sign that the treatment is being effective and that is why the cancer is reducing in size.
In some cases, the result may increase over time even if the cancer is not actually increasing in size, but this is generally more common in the case of radiotherapy treatments.