The serum concentration of retinalbinding protein (RBP), prealbumin (PA) and transferrin (TRF) was respectively determined by enzyme linked immunosorbent assay (ELISA).

• 采用酶联免疫吸附测定法（ELISA）检测血清中视黄醇结合蛋白（Retinolbindingprotein，RBP），前白蛋白（Prealbumin，PA）和转铁蛋白（Transferrin，TRF）含量。