23 Nov AFP (Alpha-Fetoprotein) Test: Purpose, Procedure & Normal Range Explained
AFP (Alpha-Fetoprotein) Test: Purpose, Procedure & Normal Range Explained
The AFP (Alpha-Fetoprotein) Test is a simple blood test that plays an important role in identifying and monitoring certain health conditions. It’s commonly used to detect liver diseases, specific cancers, and to screen for birth defects during pregnancy.
Understanding what the AFP test measures, how it’s performed, and what the results mean can help patients make informed decisions about their health with clarity and confidence.
What Is AFP (Alpha-Fetoprotein)?
Alpha-fetoprotein (AFP) is a type of plasma protein that’s naturally produced by the fetal liver, yolk sac, and gastrointestinal tract during development. In healthy adults, AFP levels remain very low.
However, if AFP levels rise abnormally, it can signal certain medical concerns — such as liver damage, hepatocellular carcinoma (a type of liver cancer), germ cell tumors, or birth defects in unborn babies.
Because of these associations, doctors often recommend the AFP test as part of diagnosis, monitoring, and prenatal screening.
Why the AFP Test Is Important
- Detecting Liver Diseases Early
AFP levels tend to rise when the liver is damaged or inflamed. Conditions such as hepatitis, cirrhosis, or liver cancer can cause these changes. Detecting them early allows doctors to begin timely treatment and prevent further complications.
- Screening for Certain Cancers
Elevated AFP levels may also occur in testicular, ovarian, or germ cell tumors. This makes AFP a helpful tumor marker — not for confirming cancer alone, but for monitoring treatment progress or spotting recurrence after therapy.
- Prenatal Screening During Pregnancy
In pregnant women, AFP levels are measured as part of maternal serum screening.
- High AFP levels may suggest neural tube defects (like spina bifida) or multiple pregnancies.
- Low AFP levels may point toward Down syndrome or Trisomy 18 (Edwards syndrome).
The results are interpreted alongside other tests and ultrasounds for accurate assessment.
When Doctors Recommend an AFP Test
Doctors may advise an AFP test for various reasons, such as:
- Screening for liver cancer in people at high risk (like those with hepatitis B or C).
- Monitoring response to cancer treatment or recurrence.
- Checking fetal health and development during pregnancy.
- Investigating unexplained symptoms such as jaundice, abdominal pain, or unintended weight loss.
- Sometimes, AFP testing is combined with other tumor markers for a clearer diagnostic picture.
How the AFP Test Works
Step 1: Sample Collection
A healthcare professional draws a small blood sample from a vein in your arm. The process is quick and only mildly uncomfortable.
Step 2: Laboratory Testing
The sample is analyzed in a certified lab using advanced methods such as immunoassays to determine AFP concentration.
Step 3: Result Interpretation
The results are compared to standard reference ranges. If levels are unusually high or low, further tests are performed to identify the cause.
Normal Range of AFP
For non-pregnant adults, AFP levels are typically:
Less than 10 ng/mL (nanograms per milliliter).
However, reference values may vary slightly from lab to lab.
In pregnancy, AFP levels naturally rise and are interpreted using a unit called Multiples of the Median (MoM), which adjusts for gestational age and other factors.
What Abnormal AFP Levels May Indicate
High AFP Levels
Elevated AFP can suggest:
- Liver conditions – hepatitis, cirrhosis, or liver cancer.
- Germ cell tumors – ovarian or testicular cancers.
- Pregnancy-related causes – neural tube defects, abdominal wall defects, or multiple gestations.
Low AFP Levels During Pregnancy
Low AFP levels may be linked with:
- Down syndrome
- Trisomy 18 (Edwards syndrome)
However, AFP results alone don’t confirm any diagnosis. They must be reviewed alongside other screenings and imaging.
Factors That Can Affect AFP Test Results
A few factors can influence AFP levels and may lead to false positives or negatives:
- Stage of pregnancy (gestational age)
- Chronic liver disorders
- Certain medications
- Laboratory variations
- Excessive alcohol intake
Because of these influences, only a qualified physician should interpret AFP results.
Is the AFP Test Safe?
Yes, the AFP test is safe and minimally invasive. You may notice slight bruising or soreness at the blood draw site, which usually goes away within a day or two. The test carries very little risk and provides valuable health insights.
What Happens If AFP Levels Are Abnormal?
If your AFP levels are outside the normal range, your doctor may suggest:
- Imaging tests like ultrasound, CT scan, or MRI to examine the liver or reproductive organs.
- Repeat AFP tests to track changes over time.
- Additional blood tests to check for other tumor markers.
- Referral to a specialist such as a hepatologist or oncologist.
Remember: Abnormal AFP results don’t always mean cancer — many benign conditions can cause similar elevations.
AFP Test in Pregnancy: A Closer Look
During pregnancy, the AFP test is often part of the second-trimester screening (between 15 and 20 weeks).
Doctors may combine AFP with other hormone tests (like hCG, estriol, and inhibin A) to perform the Quadruple Test, which offers more accurate results and minimizes false alarms.
AFP Test and Liver Cancer Monitoring
For people with chronic liver conditions — such as hepatitis B, hepatitis C, or cirrhosis — doctors may recommend periodic AFP testing.
A sudden rise in AFP could prompt further imaging or biopsy to rule out early liver cancer. When detected early, treatment success rates are significantly higher.
Final Thoughts: Understanding the AFP Test
The AFP (Alpha-Fetoprotein) Test is a valuable tool for screening and monitoring liver diseases, certain cancers, and fetal development. While it isn’t a standalone diagnostic test, it provides early warning signs that help doctors plan further investigations and timely care.
By understanding the purpose, procedure, and interpretation of the AFP test, patients and families can participate more actively in healthcare decisions. Always discuss your results with your doctor for proper guidance and next steps.
No Comments