The concentration of C-reactive protein in sera from healthy individuals.

C-reactive protein (CRP) in a concentration of 0.02-13.5 mg/l was regularly demonstrated in sera obtained from apparently healthy children and adults of both sexes. CRP must therefore be considered a normal constituent of serum. A weak positive correlation was found between CRP concentration and age. No significant difference in CRP concentration was demonstrable between men and non-pregnant women. Neither was any such difference found between females using oral contraceptives and controls.