The kit is used for quantitative determination of testosterone (T) in human serum in vitro. Testosterone and FSH jointly promote sperm formation and maturation, and are related to sperm motility and sperm tube metabolism. Testosterone can also promote protein synthesis, weaken amino acid catabolism, positive nitrogen balance, promote bone thickening, calcium deposition, epiphysis fusion; testosterone can promote the absorption of Na + in distal convoluted tubules, Cl - can cause edema, reduce the excretion of K + and inorganic phosphate from urine; testosterone can promote the formation of red blood cells in bone marrow; testosterone can increase the basic metabolic rate, and also make creatine and ATP react to synthesize creatine phosphate. The determination of plasma testosterone is helpful for the diagnosis of some endocrine diseases, and also important for the study of the pharmacological effect and experimental research of oral contraceptives.