Serum amyloid A: an extremely sensitive marker for intensity of tissue damage in trauma patients and indicator of acute response in various diseases.

Acute response after traumatic events was studied in serial serum samples of 21 patients over a period of 13 days. Among the various biochemical and hematologic parameters, serum amyloid A (SAA) exhibited the most striking changes, with a pattern similar to that of the tissue marker creatine-P kinase (CPK). Maximal SAA level was detected 3-4 days after onset of the event, and reached 216 +/- 41 SEM gm/ml (normal range less than 2 gm/ml), while maximal CPK level was detected on the same day and reached 530 +/- 242 SEM IU/L (normal range 24-195 IU/L). Fibrinogen, leucocytes, platelets, albumin, alkaline phosphatase (AP), and calcium (Ca) each showed its own typical pattern of change. Fever did not develop. Comparison of SAA levels after various acute events suggests that damage to the myocardium is the most powerful stimulus for SAA induction, followed by traumatic events, arthritis, viral infections, and malignant diseases. It seems therefore that although acute response is considered a generalized reaction, it is not completely independent of the localized events which induce it. Among the known parameters, SAA is the most sensitive marker for monitoring the intensity of events.