Clinical Significance

Prealbumin is a tryptophan‑rich protein which is synthesized in hepatocytes and has a molar mass of 55000 daltons. At a pH of 8.6, an electrophoretic band appears prior to albumin in a relative amount of < 2.5 % due to its greater rate of diffusion to the anode. Its function is to bind and transport low molecular weight retinol-binding proteins (molar mass of less than 21000 daltons), preventing their glomerular filtration. 30‑50 % of circulating prealbumin is complexed by retinol‑binding protein. Furthermore, it binds and transports thyroxine (T4), nevertheless its affinity to this hormone is less than that of thyroxine-binding globulin.  

Prealbumin has a short half-life of approximately 2 days. Accordingly, decreased hepatocellular synthesis caused by acute liver damage or dietary protein deficiency elicits a very rapid decrease in serum prealbumin levels. According to the literature, prealbumin can act as a negative acute phase reactant, with its concentration decreasing rapidly during inflammatory processes.  

_{Source: Roche Cobas PREA Method Sheet Version 3.0 2025-02}