Alpha-fetoprotein Blood Test (cont.)
Tse-Ling Fong, MD
Dr. Fong is the Medical Director of the USC Liver Transplant Program and Associate Professor of Medicine at the USC Keck School of Medicine. He obtained his medical degree from the University of Southern California and completed his residency in Internal Medicine at Los Angeles County-USC Medical Center. He is board certified in Internal Medicine and the subspecialty of Gastroenterology.
Leslie J. Schoenfield, MD, PhD
Dr. Schoenfield served as associate professor of medicine and consultant in gastroenterology on the faculty of the Mayo Clinic for seven years. He became a professor of medicine in residence at UCLA from 1972 to 1999 (now emeritus). He was the director of gastroenterology at Cedars-Sinai Medical Center in Los Angeles for 25 years, where he received the chief resident's teaching award, the president's award, and the pioneer of medicine award.
In this Article
- What is alpha-fetoprotein (AFP) blood test?
- In which situations are high blood levels of AFP seen?
- What tests are available for measuring AFP?
- What is the sensitivity of AFP for diagnosing liver cancer?
- Are there other liver cancer markers available for diagnosing liver cancer?
In which situations are high blood levels of AFP seen?
In adults, high blood levels (over 500 nanograms/milliliter) of AFP are seen in only three situations:
- Germ cell tumors (cancer of the testes and ovaries)
- Metastatic cancer in the liver (originating in other organs)
What tests are available for measuring AFP?
Several assays (tests) for measuring AFP are available. Generally, normal levels of AFP are below 10 ng/ml. Moderate levels of AFP (even almost up to 500 ng/ml) can be seen in patients with chronic hepatitis. Moreover, many patients with various types of acute and chronic liver diseases without documentable liver cancer can have mild or even moderate elevations of AFP.
What is the sensitivity of AFP for diagnosing liver cancer?
The sensitivity of AFP for liver cancer is about 60%. In other words, an elevated AFP blood test is seen in about 60% of liver cancer patients. That leaves 40% of patients with liver cancer who have normal AFP levels. Therefore, a normal AFP does not exclude liver cancer. Also, as noted above, an abnormal AFP does not mean that a patient has liver cancer. It is important to note, however, that patients with cirrhosis and an abnormal AFP, despite having no documentable liver cancer, still are at very high risk of developing liver cancer. Thus, any patient with cirrhosis and an elevated AFP, particularly with steadily rising blood levels, will either most likely develop liver cancer or actually already have an undiscovered liver cancer.
An AFP greater than 500 ng/ml is very suggestive of liver cancer. In fact, the blood level of AFP loosely relates to (correlates with) the size of the liver cancer. Finally, in patients with liver cancer and abnormal AFP levels, the AFP may be used as a marker of response to treatment. For example, an elevated AFP is expected to fall to normal in a patient whose liver cancer is successfully removed surgically (resected).
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