Elevated Alpha-Fetoprotein: What Does It Mean?

When alpha-fetoprotein (AFP) levels are elevated, it's important to consider the possibility of primary liver cancer. However, it's also common for AFP levels to rise during pregnancy, which is typically a normal and temporary occurrence.

Primary Liver Cancer and AFP Levels

One of the most significant concerns when AFP levels rise is the potential presence of primary liver cancer. In patients with hepatocellular carcinoma, AFP levels in the blood often increase dramatically. A serum AFP level greater than 400 μg/L is commonly used as a diagnostic threshold for liver cancer. However, not all elevated AFP levels indicate cancer.

Transient Elevations in AFP

If AFP levels are elevated but remain below 500 μg/L, the increase may be transient. This can occur in conditions such as viral hepatitis or fulminant hepatitis. In these cases, the rise in AFP is usually temporary and resolves with treatment or as the underlying condition improves.

What If AFP Levels Stay High?

When AFP levels significantly increase and remain elevated, primary liver cancer should be strongly considered. Specifically, if AFP levels exceed 500 μg/L for four consecutive weeks or remain above 200 μg/L for eight weeks, it may indicate hepatocellular carcinoma. However, these levels must be interpreted carefully after ruling out pregnancy and germ cell tumors, which can also cause AFP to rise.

Confirming a Liver Cancer Diagnosis

To confirm a diagnosis of primary liver cancer, additional tests are necessary. These may include abdominal ultrasound, computed tomography (CT) scans, or magnetic resonance imaging (MRI). In some cases, a liver biopsy may be required to obtain a definitive diagnosis through pathological analysis.

Physiological Causes of Elevated AFP

For pregnant women, elevated AFP levels are often a normal part of pregnancy. AFP is produced by the fetal liver, and levels can be detected in the mother's blood during gestation. Therefore, it's essential to differentiate between physiological increases and those caused by underlying medical conditions.