Variability and classification accuracy of serial high-sensitivity C-reactive protein measurements in healthy adults.
BACKGROUND
Increased concentrations of high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation, are associated with increased risk for coronary heart disease. Because of its relationship to inflammation, hs-CRP has considerable biologic variation. This study was carried out to characterize CRP variation and to compare it to another risk factor, total serum cholesterol.


METHODS
One hundred thirteen individuals were scheduled to have five measurements each of hs-CRP and total cholesterol carried out at quarterly intervals over a 1-year period. Variations of hs-CRP and total cholesterol were characterized, and classification accuracy was described and compared for both.


RESULTS
The relative variation was comparable for hs-CRP and total cholesterol. When classified by quartile, 63% of first and second hs-CRP measurements were in agreement; for total cholesterol it was 60%. Ninety percent of hs-CRP measurements were within one quartile of each other. This relationship was not altered by the use of log-transformed hs-CRP data.


CONCLUSIONS
hs-CRP has a degree of measurement stability that is similar to that of total cholesterol.
Department of Medicine, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, MA 01655, USA. ira.ockene@umassmed.edu.
I S
IS
Ockene
C E
CE
Matthews
N
N
Rifai
P M
PM
Ridker
G
G
Reed
E
E
Stanek
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002097:C-Reactive Protein / Q000032:analysis*; D002784:Cholesterol / Q000097:blood; D005260:Female; D006801:Humans; D007118:Immunoassay; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D012016:Reference Values; D012737:Sex Factors
D002097:C-Reactive Protein; D002784:Cholesterol