Acute phase protein response to infection in elderly patients.

The presence of infection is often difficult to diagnose in elderly patients. In view of this, laboratory markers of infection are of great clinical importance. The pattern of change in acute phase proteins has not hitherto been studied in elderly patients. In a prospective series of 114 acute elderly admissions to a Geriatric Unit there was a significant change with infection in all proteins studied, but C-reactive protein was the most sensitive marker of the presence and severity of infection and the response to antimicrobial therapy. The best pair of acute phase proteins in the prediction of infection were alpha 1-acid glycoprotein and C-reactive protein whilst albumin and alpha 1-acid glycoprotein together contributed significantly to the prediction of outcome.