What is the significance of elevated alpha-fetoprotein (AFP) in a newborn?

From the Guidelines

Elevated alpha-fetoprotein (AFP) in a newborn is a significant finding that warrants prompt medical evaluation to rule out underlying conditions such as liver disorders, cancers, or genetic disorders. The significance of elevated AFP in a newborn is multifaceted, as it can indicate several conditions, including liver disorders like biliary atresia or hepatitis, certain cancers such as hepatoblastoma or germ cell tumors, or genetic disorders like ataxia-telangiectasia 1.

Key Considerations

• Elevated AFP levels may be due to various factors, and a thorough evaluation is necessary to determine the underlying cause.
• The management approach involves identifying the underlying cause through additional testing, which typically includes liver function tests, abdominal ultrasound, and possibly genetic testing.
• No specific medication is indicated for high AFP itself, as treatment targets the underlying condition.
• For example, biliary atresia requires surgical intervention with the Kasai procedure, while hepatitis may need antiviral therapy depending on the cause.
• Parents should be aware that AFP levels naturally decrease during the first year of life, so serial measurements may be necessary to monitor trends.
• The significance of elevated AFP relates to its role as a marker for developing tissues; persistent elevation suggests ongoing abnormal cell growth or liver dysfunction that requires investigation.

Screening and Monitoring

• According to the study by Kalish et al. 1, AFP screening is sensitive for hepatoblastoma (HB) and can be used to distinguish hemangiomas compared to HB detected by imaging.
• The study recommends full abdominal ultrasound and simultaneous serum AFP screening every 3 months starting at birth (or at the time of diagnosis) and should continue through the child’s 4th birthday for patients with certain syndromes.
• In monitoring AFP levels, the individual value needs to be interpreted in the context of the AFP trend over time, with an expectation of declining values through infancy 1.

Clinical Implications

• Any newborn with high AFP should be referred to a pediatric specialist for comprehensive evaluation.
• The interpretation of elevated AFP levels in young infants should be done with caution, as this is commonly a normal finding in healthy neonates 1.
• Ongoing AFP measurements are mandatory, especially in cases where the underlying condition is suspected to be related to liver disease or cancer.

From the Research

Significance of Elevated Alpha-Fetoprotein (AFP) in Newborns

Elevated alpha-fetoprotein (AFP) levels in newborns can be indicative of several conditions, including:

• Fetal demise or abnormalities, such as neural tube defects 2
• Certain malignancies, like hepatoblastoma and germ cell tumors 2, 3
• Hepatobiliary disorders, including neonatal cholestasis 4
• Congenital nephrosis 5

Reference Values for AFP in Newborns

Normal reference values for AFP in newborns have been defined, with a reference interval of 15.7-146.5 microg/ml at birth, based on a 95% confidence interval 6. The median value of 48.3 microg/ml is also a useful reference. However, it is essential to note that AFP levels can vary widely, and reference intervals should be interpreted with caution.

Correlation with Gestational Age and Birthweight

A significant negative correlation has been found between AFP serum levels and gestational age, as well as birthweight 6. This suggests that AFP levels tend to decrease as gestation advances and the newborn weighs more.

Diagnostic Value of AFP

The diagnostic value of AFP is high, particularly when compared to normal ranges 3. Elevated AFP levels can be associated with certain conditions, such as steatosis and AST elevation in neonatal cholestasis 4. However, it is crucial to consider the wide range of normal values and interpret results in the context of the individual patient's clinical presentation.