A fetoprotein of 12ug/L is not a disease. Alpha-fetoprotein is a serum glycoprotein synthesized by the liver and yolk sac during early fetal life, and synthesis of alpha-fetoprotein is quickly suppressed after birth. When a malignant lesion occurs in the liver cells or embryonic tissues of the gonads, the gene in question is reactivated, causing the cells that have lost the ability to synthesize alpha-fetoprotein to synthesize it again, resulting in elevated blood levels. The reference value of alpha-fetoprotein is <25ug/L in serum, which may vary from hospital to hospital due to differences in equipment, and needs to be combined with the actual clinical situation. Elevated alpha-fetoprotein can be seen in primary liver cancer, embryonic tumors of the gonads, gastric cancer, pancreatic cancer, as well as viral hepatitis, pregnancy and so on. Fetoprotein 12ug/L is within the normal range, so related diseases are not considered for the time being. If there is any abnormality, it is necessary to consult a doctor in time and not to avoid medical treatment to avoid delaying the condition.