It is normal for alpha-fetoprotein to fluctuate within the normal range; it fluctuates with physical conditions. If it is outside the range, the possibility of disease should be considered. Alpha-fetoprotein (AFP) is a glycoprotein that is synthesized primarily by fetal liver cells and the yolk sac. Its normal reference range is <20ug/L (20ng/mL). The value of alpha-fetoprotein fluctuates due to other physical conditions and as long as it is within the normal range, it is normal. However, alpha-fetoprotein is significantly elevated in newborns, pregnant women, and also in patients with acute and chronic hepatitis, with genital tumors, and hepatocellular liver cancer. However, except for malignant tumors, it usually does not exceed 400ug/L. If the alpha-fetoprotein fluctuates within the normal range, there is no need to worry too much.