C-reactive protein levels are used as a criterion for initiating statin therapy and are also included in some risk scores for predicting cardiac events. It is sobering to learn from this report that there is so much intrapatient variability with the test: one-third of patients with a high value will have a normal value if the test is repeated soon afterward. Clinical decisions and risk prediction should be made based on at least 2 similar CRP levels.
Redberg RF. Laboratory Variability and Precise Clinical Decision MakingComment on “Within-Person Variability in High-Sensitivity C-Reactive Protein”. Arch Intern Med. 2012;172(19):1521. doi:10.1001/archinternmed.2012.4202