Prealbumin (PA), synthesized by hepatocytes, shows up in front of albumin during electrophoresis and has a half-life of about 12 hours. Clinical determination of prealbumin concentration in plasma is more sensitive for understanding protein malnutrition, liver insufficiency, than albumin and transferrin. The main reason for high prealbumin is caused by blood concentration, which gains the strong metabolic capacity of the liver. Liver diseases such as hepatocellular carcinoma, cirrhosis, chronic active hepatitis, and obstructive jaundice can be manifested as low prealbumin. In general, increased prealbumin, transaminases and bilirubin are mostly associated with acute liver diseases, especially in patients with liver cancer and obstructive jaundice, and if prealbumin continues to decrease, it indicates continued deterioration of the disease. In addition to being a sensitive indicator of nutritional protein, PA decreases in its blood concentration in acute inflammation, malignancy, cirrhosis or nephritis. 1, Prealbumin is more sensitive in liver disease, and it has been suggested that 30% of patients with normal albumin have reduced prealbumin in liver disease and almost zero in necrotizing cirrhosis. Cirrhosis hepatocyte necrosis is lighter, prealbumin changes little, the prognosis is better, when the condition improves, prealbumin also rapidly increased. 2, subacute liver necrosis prealbumin has been at low values, so prealbumin can be used as an indicator to determine the prognosis of liver disease. It can be reduced in patients with hepatocellular carcinoma and obstructive jaundice, and the degree of reduction is closely related to the disease. 3, combined with transaminase, bilirubin test for different types of liver disease and non-hepatic disease has the significance of differentiation, such as pre-albumin, transaminase, bilirubin are increased, most of the acute liver disease, such as pre-albumin is not increased, only transaminase, bilirubin increased should be considered non-hepatic disease itself. 4, nephrotic syndrome before albumin not only does not decrease, but also can be elevated when the diet is adequate. Pre-albumin decreases in malnutrition negative nitrogen balance.