Variability and classification accuracy of serial high-sensitivity C-reactive protein measurements in healthy adults
Department of Medicine, Division of Cardiovascular Medicine; Department of Medicine, Division of Preventive and Behavorial Medicine
Adult; Aged; Analysis of Variance; C-Reactive Protein; Cholesterol; Female; Humans; Immunoassay; Longitudinal Studies; Male; Middle Aged; Nephelometry and Turbidimetry; Reference Values; Sex Factors
Cardiology | Cardiovascular Diseases
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.
CONCLUSION: hs-CRP has a degree of measurement stability that is similar to that of total cholesterol.
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Citation: Clin Chem. 2001 Mar;47(3):444-50.