title: C-reactive protein in population samples.
abstract: The significance of C-reactive protein (CRP) was studied in three different sets of specimens. Raised levels (greater than 10 mg/l) were detected in 2.0% of 380 healthy blood donors from whom two blood specimens, taken at an interval of half a year, were tested. Except for two cases, only one of the two specimens was positive. Raised levels were found three times as frequently (in 6.6%) in a random middle-aged population sample consisting of 531 subjects. More than 40% of the raised levels could be connected to acute respiratory infections, and about 20% to smoking. Five of the 35 subjects (14%) in the population sample with elevated CRP had rheumatoid arthritis. The third set of sera comprised pre-illness specimens from 22 subjects who developed rheumatoid arthritis a few months to five years later. Although it had previously been proved that the majority of these sera contained rheumatoid factors, the CRP concentration was increased in one specimen only.
mesh_terms: D000208:Acute Disease; D001172:Arthritis, Rheumatoid / Q000097:blood*; D002097:C-Reactive Protein / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D012016:Reference Values; D012141:Respiratory Tract Infections / Q000097:blood*; D012907:Smoking
chemical_list: D002097:C-Reactive Protein