Patients with thermal injury have subclinical disseminated intravascular coagulation (DIC) and increased hypercoagulability. This study was undertaken to determine whether prothrombin fragment 1.2 (F1.2) or modified antithrombin (ATM) were predictive of DIC or thrombotic risk in thermal injury. Sixty burn patients had F1.2 and ATM plasma levels drawn within 36 hours and between days 5 and 7 after injury. Additional hemostatic parameters were evaluated in a subset of nine patients with abnormal global coagulation markers (an elevated prothrombin time [PT], or activated partial thromboplastin time [aPTT]) or decreased platelets, but without clinical evidence of DIC, and three patients with DIC at admission. These patients were matched for age and %TBSA with 12 control patients who had normal PT, aPTT, and platelets. Blood was drawn for hemostatic factors: fibrinogen, antithrombin, F1.2, ATM, and D-dimer. F1.2 plasma levels increased in proportion to the severity of the %TBSA. The levels were significantly increased among burn patients with 20 to 40% and >40% TBSA at admission compared with normal (P < .01). ATM showed a significant decrease (P < .02) compared with normal levels and remained decreased for the first 5 to 7 days of the acute clinical phase in all the groups. Control patients and those with DIC had significantly increased D-dimer (P < .0001) and F1.2, (P < .03) plasma levels, and decreased antithrombin (P < .0001) compared with normal values; ATM plasma levels were not significantly different among the groups (P < .28). Burn patients with abnormal global coagulation markers had significantly increased D-dimer (P < .0001) and ATM (P < .005) plasma levels and decreased antithrombin levels (P < .0001) compared with normal values; F1.2 plasma levels were not significantly different (P < .15). Neither F1.2 nor ATM plasma levels showed any advantage in predicting thrombosis or DIC compared with PT, aPTT, and platelet count in conjunction with the patient’s clinical presentation.