General Health

AFP Level Test and Its Sensitivity as a Tumour Marker

Overview

A protein called alpha-fetoprotein (AFP) is formed in the liver of a growing foetus. Some AFP crosses across the placenta and into the maternal circulation throughout the baby’s growth. AFP can also be used to confirm a diagnosis of liver cancer, ovarian cancer, or testicular cancer. High levels of AFP can sometimes indicate additional malignancies, such as Hodgkin’s disease and lymphoma, as well as noncancerous liver diseases. The concentration of AFP in pregnant women during the second trimester of pregnancy is measured with an AFP test. An increasing or decreasing level of AFP in a mother’s blood might indicate a birth defect or other problem.

Due to changes in AFP levels throughout pregnancy, the due date is often miscalculated.

  • A neural tube defect is a significant disorder that causes improper brain and/or spine development in a growing newborn.
  • Down syndrome is a genetic condition that causes developmental delays and intellectual difficulties.
  • Because more than one baby produces AFP, twins or multiple births are a possibility.

AFP level test can be employed for the following :

According to various health care associations, between the 15th and 20th week of pregnancy, all pregnant women should be provided with an AFP test. The exam may be particularly significant if the pregnant mother has:

  • If the individual has a history of birth abnormalities in their family
  • If the pregnant mother is above the age of 35
  • If the pregnant mother is diabetic
  • Or He/she has hepatocellular carcinoma (HCC) which is a kind of primary liver cancer;
  • Germ cell malignancies (testicular and ovarian cancers include embryonal carcinoma and yolk sac tumours); and
  • Ataxia-telangiectasia is a rare inherited neurological illness that causes significant disability.

Risk factors

An AFP blood test poses very little risk to the pregnant mother or her baby. There may be some discomfort or bruising where the needle was inserted, but most symptoms fade promptly. Another test, amniocentesis, is more accurate in diagnosing Down syndrome and other birth problems, but it carries a slight risk of miscarriage.

Sensitivity of AFP as a tumour marker

In some forms of chronic liver illness, primary liver cancer, also known as hepatocellular carcinoma or hepatoma, is more common. AFP has a sensitivity of about 70% for liver cancer as a screening tool in patients with chronic hepatitis B and C or hemochromatosis. In other words, around 70% of persons with primary liver cancer have an elevated AFP blood test. About 30% of patients in these high-risk groups may develop liver cancer while having normal AFP levels. As a result, the test is not diagnostic but rather serves as a red flag. As a result, a normal AFP doesn’t rule out liver cancer. In a patient with fibrolamellar carcinoma, a kind of hepatocellular carcinoma, for example, AFP levels are normal.

As previously stated, an abnormal AFP does not necessarily indicate liver cancer. However, even if there is no evidence of liver cancer, patients with cirrhosis (scarring) of the liver and an abnormal AFP are still at a very high risk of developing liver cancer. As a result, anyone with cirrhosis and an increased AFP, especially one with progressively increasing blood levels of AFP, is either at risk of developing liver cancer or already has one.

An AFP level of 500 ng/ml or more is highly predictive of liver cancer. The AFP level in the blood has a loose relationship (correlation) with the extent of liver cancer.

Finally, abnormal AFP levels in patients with liver cancer may be utilised as a measure of therapeutic efficacy. When a patient’s liver cancer is surgically removed, for example, a high AFP is expected to return to normal. Recurrence of liver cancer is likely if AFP elevates again.

The AFP is measured at diagnosis and tracked as a tumour marker in certain malignancies of the testis, as described above, like that described above in patients with liver cancer.

In normal, healthy individuals, AFP is not considered a screening test for cancer detection.

Reference ranges

Test results may differ depending on the individual’s age, sex, medical history, test method, and other factors. It’s possible that the test results don’t indicate a disorder. Individuals can inquire with the clinician about the implications of their test results.

The concentration of AFP is expressed in nanograms per millilitre (ng/mL). For adults, an AFP level of 10 to 20 ng/mL is considered normal. A blood level of AFP of more than 400 ng/mL could indicate the presence of liver tumours.

Other malignancies, such as Hodgkin’s disease, lymphoma, and renal cell carcinoma, may have elevated AFP levels (kidney cancer).

The AFP level will not be elevated in all patients with these malignancies. Furthermore, increased AFP levels may indicate cirrhosis or persistent acute hepatitis.

Author

 Yash Batra

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