What are the screening tests for fatty liver? So what is fatty liver? Fatty liver is commonly referred to as an excessive accumulation of fatty tissue in the liver, which leads to liver cell damage. Generally speaking, fatty liver can be divided into three types: mild, moderate and severe. First of all, we can usually take blood tests for liver function to evaluate the degree of liver damage, such as portal aminotransferase (AST), alanine aminotransferase (ALT) and bilirubin. Mild fatty liver function generally does not change much, once the liver function indicators are elevated often indicates moderate, or severe fatty liver, severe fatty liver indicators can be more than 5 times higher than normal. Secondly, ultrasound examination is more sensitive and is a common means to diagnose fatty liver, and can be used to grade fatty liver with respect to the fineness of liver tissue and ultrasound attenuation. Again, CT scan can reveal that the CT density of fatty liver is significantly lower than that of the spleen, and the severity of fatty liver can be assessed by comparing the density values of the liver and spleen. However, CT examination is less sensitive than ultrasound examination. Finally, pathological examination is the gold standard for the diagnosis of fatty liver. Liver tissue aspiration biopsy is mainly used for differential diagnosis of atypical fatty liver from other liver lesions. Because of its invasive nature, it is generally not preferred as an examination.