Fucoidan is a kind of lysosomal acid hydrolase, which is mainly used in the detection of liver cancer. The normal value of fucoidan is not more than 40U/L, and the high value of 39.9 suggests that there may be cirrhosis of the liver, hepatitis, or pregnancy, which needs to be analyzed together with other tests. Fucoidan is commonly used in the detection of primary liver cancer. Primary liver cancer mainly relies on alpha-fetoprotein for screening and detection, but there are some patients whose alpha-fetoprotein cannot be clearly detected, so it is necessary to carry out the fucoidan test at this time, and fucoidan has a clear significance in the diagnosis of liver cancer. The low limit of normal value of fucoidan is 3~5U/L, and the high value is 35~40U/L. Fucoidan, if only mildly elevated, may be the result of cirrhosis, hepatitis, ovarian tumors, tumors of embryonic origin and pregnancy. People who have been drinking alcohol for a long time may also have high fucoidan, so it is necessary to combine with other tests for further diagnosis. If the fucoidan is simply high but there are no other abnormal lesions, it does not mean that the index has obvious significance. If the fucoidan is much higher than 40U/L, we should be alert to the occurrence of liver cancer, and need to carry out further examination in time, such as ultrasound of the liver, CT or MRI of the liver, etc., so as to make a clear diagnosis under the guidance of the doctor.