Prealbumin is synthesized by the liver, and its level can usually be used as a reference for the state of health of the body. The dangers of low prealbumin include decreased immune function, vitamin A deficiency, lower limb edema, etc. It may also indicate that the organism is suffering from malnutrition and liver disease. 1. Harms of low prealbumin: (1) Decrease in immune function: prealbumin is a kind of tissue repair material with immune effect, and its low level may cause decrease in immune function. (2) Vitamin A deficiency: Pre-Albumin is the transporter protein of vitamin A. Low levels of pre-Albumin will affect the transporter of vitamin A, which may lead to dry eyes, dry skin, dry hair, night blindness and other symptoms triggered by vitamin A deficiency. (3) Lower limb edema: Prealbumin works with albumin to maintain the colloid osmotic pressure of the body’s blood, and low levels of prealbumin may lead to lower limb edema. 2. Low prealbumin suggests diseases: (1) Malnutrition: As a sensitive indicator of nutritional proteins, low levels of prealbumin may indicate malnutrition. (2) Liver disease: prealbumin as an indicator of early liver function damage, prealbumin is low, suggesting the existence of liver lesions or functional damage, such as chronic hepatitis, cirrhosis, hepatocellular carcinoma and other diseases. When low prealbumin exists, patients should do the next examination and treatment under the guidance of doctors.