Alterations in plasma antithrombin III following total hip replacement and elective cholecystectomy.

Antithrombin III activity and immunoreactive antithrombin III was determined in 31 patients before elective surgery and 3 h, 1, 3 and 7 d after. The values fell about 10–20% from 3 h to 3 d, but had returned to preoperative levels by the seventh day. A fall to 40% was seen. The fall in activity was a little smaller than the fall in immunoreactive protein.