β2-MG (β2-microglobulin) is a β-light chain of human leukocyte antigen molecules. Its main function is to participate in lymphocyte surface recognition and is related to killer cell receptor. Almost all nucleated cells in the body can synthesize β2-MG and attach to cell surface. The daily production of β2-MG remains constant and is secreted into various body fluids. β2-MG is produced in lymphocytes and is rarely present in urine because it can pass freely through the glomerular filtration membrane due to low molecular weight. β2-MG filtered from the glomeruli is almost entirely reabsorbed through the tubules. Increased urinary β2-MG excretion indicates tubular reabsorption disorder, called tubular proteinuria. In clinical urine examination, urinary β2-MG is of great significance for the detection of nephropathy.This product is the recombinant human β2-MG protein expressed from human 293 cells (HEK293).