[A study on a postoperative change of beta-2-microglobulin in surgical patients]

Various renal tubular functions were monitored perioperatively in 42 surgical patients and the validity of beta-2-microglobulin (BMG) was evaluated. NAG index (urine NAG titer/urine creatinine), the absolute value of free water clearance and fractional excretion of sodium were worse at 3 to 5 hours after the beginning of operation, indicating the latent renal tubular damage took place during operation. On the other hand, fractional excretion of BMG (FE-BMG; BMG clearance/creatinine clearance) slowly elevated after operation and reached a peak on the 2nd postoperative day. The postoperative change of C-reactive protein (CRP), was similar with that of FE-BMG, showing a significant correlation (r = 0.716, p less than 0.001). The close relationship between CRP and FE BMG was confirmed in 26 patients with or without abnormal liver function who underwent abdominal operation. The peak value of FE BMG was significantly (p less than 0.01) lower in 5 patients with ICG 15' greater than 25% than in 21 patients with ICG 15' less than 20%. Similarly, the peak value of CRP tended to be lower in the former group. In conclusion, FE BMG can not be employed as an indicator of renal tubular function during postoperative period. It reacts as an acute phase reactant like CRP and is probably produced in the liver.