Analytic Issues for Clinical Use of C-Reactive Protein

  • Nader Rifai
Part of the Contemporary Cardiology book series (CONCARD)


The serum concentration of C-reactive protein (CRP) has historically been used to detect active infection and inflammation. Recent evidence has demonstrated that slight increases in CRP concentration, within the normal range, can predict future vascular events, thus reflecting the inflammatory component of atherosclerosis. It was necessary to develop new high-sensitivity methods for this clinical application, and to establish cut points for risk assessment of cardiovascular risk. To avoid misclassification of individuals into inappropriate categories of risk, clinicians and investigators must have an understanding of preanalytic and analytic sources of errors in CRP measurement. This chapter addresses issues that contribute to the reliability of CRP evaluation such as physiological variability, appropriate sample handling, and method standardizations.

Key Words

C-reactive protein measurement standardization interpretation 


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  1. 1.
    Biasucci LM, Vitelli A, Liuzzo G, et al. Elevated levels of interleukin-6 in unstable angina. Circulation 1996;94:874–877.PubMedGoogle Scholar
  2. 2.
    Blankenberg S, Luc G, Ducimetiere P, et al. Interleukin-18 and the risk of coronary heart disease in European men: the Prospective Epidemiological Study of Myocardial Infarction (PRIME). Circulation 2003;108:2453–2459.CrossRefPubMedGoogle Scholar
  3. 3.
    Ridker PM, Buring JE, Rifai N. Soluble P-selectin and the risk of future cardiovascular events. Circulation 2001;103:491–495.PubMedGoogle Scholar
  4. 4.
    Ridker PM, Hennekens CH, Buring JE, Rifai N. C-reactive protein and other markers of inflammation in the prediction of cardiovascular disease in women. N Engl J Med 2000;342:836–843.CrossRefPubMedGoogle Scholar
  5. 5.
    Johnson BD, Kip KE, Marroquin OC, et al. Serum amyloid A as a predictor of coronary artery disease and cardiovascular outcome in women: the National Heart, Lung, and Blood Institute-Sponsored Women’s Ischemia Syndrome Evaluation (WISE). Circulation 2004;109:726–732.CrossRefPubMedGoogle Scholar
  6. 6.
    Danesh J, Muir J, Wong YK, Ward M, Gallimore JR, Pepys MB. Risk factors for coronary heart disease and acute-phase proteins: a population-based study. Eur Heart J 1999;20:954–959.CrossRefPubMedGoogle Scholar
  7. 7.
    Ledue TB, Weiner DL, Sipe JD, Poulin SE, Collins MF, Rifai N. Analytical evaluation of particleenhanced immunonephelometric assays for C-reactive protein, serum amyloid A and mannose-binding protein in human serum. Ann Clin Biochem 1998;35:745–753.PubMedGoogle Scholar
  8. 8.
    Kimberly MM, Vesper HW, Caudill SP, et al. Standardization of immunoassays for measurement of high-sensitivity C-reactive protein (hsCRP). Phase I: evaluation of secondary reference materials. Clin Chem 2003;49:611–616.CrossRefPubMedGoogle Scholar
  9. 9.
    Pearson TA, Mensah GA, Alexander RW, et al. Markers of inflammation and cardiovascular disease: application to clinical and public health practice: a statement for healthcare professionals from the Centers for Disease Control and Prevention and the American Heart Association. Circulation 2003;107:499–511.CrossRefPubMedGoogle Scholar
  10. 10.
    Pepys MB, Hirschfield GM. C-reactive protein: a critical update. J Clin Invest 2003;111:1805–1812.PubMedGoogle Scholar
  11. 11.
    Castell JV, Gomez-Lechon MJ, David M, Fabra R, Trullenque R, Heinrich PC. Acute-phase response of human hepatocytes: regulation of acute-phase protein synthesis by interleukin-6. Hepatology 1990;12: 1179–1186.CrossRefPubMedGoogle Scholar
  12. 12.
    Hoffmann JA, Kafatos FC, Janeway CA, Ezekowitz RA. Phylogenetic perspectives in innate immunity. Science 1999;284:1313–1318.CrossRefPubMedGoogle Scholar
  13. 13.
    Clyne B, Olshaker JS. The C-reactive protein. J Emerg Med 1999;6:1019–1025.CrossRefGoogle Scholar
  14. 14.
    Erlandsen EJ, Randers E. Reference interval for serum C-reactive protein in healthy blood donors using the Dade Behring N Latex CRP mono assay. Scand J Clin Lab Invest 2000;60:37–43.CrossRefPubMedGoogle Scholar
  15. 15.
    Hutchinson WL, Köenig W, Frohlich M, Sund M, Lowe GD, Pepys MB. Immunoradiometric assay of circulating C-reactive protein: age-related values in the adult general population. Clin Chem 2000;46: 934–938.PubMedGoogle Scholar
  16. 16.
    Herberth B, Siest G, Henny J. High-sensitivity C-reactive protein (CRP) reference intervals in the elderly. Clin Chem Lab Med 2001;11:1169, 1170.CrossRefGoogle Scholar
  17. 17.
    Rifai N, Ridker PM. Population distributions of C-reactive protein in apparently healthy men and women in the United States: implication for clinical interpretation. Clin Chem 2003;49:666–669.CrossRefPubMedGoogle Scholar
  18. 18.
    Ford ES, Giles WH, Myers GL, Mannino DM. Population distribution of high-sensitivity C-reactive protein among US men: findings from National Health and Nutrition Examination Survey 1999–2000. Clin Chem 2003;49:686–690.CrossRefPubMedGoogle Scholar
  19. 19.
    Imhof A, Frohlich M, Loewel H, et al. Distributions of C-reactive protein measured by high-sensitivity assays in apparently healthy men and women from different populations in Europe. Clin Chem 2003;49: 669–672.CrossRefPubMedGoogle Scholar
  20. 20.
    Yamada S, Gotoh T, Nakashima Y, et al. Distribution of serum C-reactive protein and its association with atherosclerotic risk factors in a Japanese population: Jichi Medical School Cohort Study. Am J Epidemiol 2001;153:1183–1190.CrossRefPubMedGoogle Scholar
  21. 21.
    Albert MA, Glynn RJ, Buring J, Ridker PM. C-reactive protein levels among women of various ethnic groups living in the United States (from the Women’s Health Study). Am J Cardiol 2004;93:1238–1242.CrossRefPubMedGoogle Scholar
  22. 22.
    Crawford VL, Sweeney O, Coyle PV, Halliday IM, Stout RW. The relationship between elevated fibrinogen and markers of infection: a comparison of seasonal cycles. QJM 2000;93:745–750.CrossRefPubMedGoogle Scholar
  23. 23.
    Ockene IS, Matthews CE, Rifai N, Ridker PM, Reed G, Stanek E. Variability and classification accuracy of serial high-sensitivity C-reactive protein measurements in healthy adults. Clin Chem 2001;47:444–450.PubMedGoogle Scholar
  24. 24.
    Clark GH, Fraser CG. Biological variation of acute phase proteins. Ann Clin Biochem 1993;30:373–376.PubMedGoogle Scholar
  25. 25.
    Macy EM, Hayes TE, Tracy RP. Variability in the measurement of C-reactive protein in healthy subjects: implications for reference intervals and epidemiological applications. Clin Chem 1997;43:52–58.PubMedGoogle Scholar
  26. 26.
    Kluft C, de Maat MP. Determination of the habitual low blood level of C-reactive protein in individuals. Ital Heart J 2001;2:172–180.PubMedGoogle Scholar
  27. 27.
    Ledue TB, Rifai N. Preanalytic and analytic sources of variations in C-reactive protein measurement: implications for cardiovascular disease risk assessment. Clin Chem 2003;49:1258–1271.CrossRefPubMedGoogle Scholar
  28. 28.
    Ridker PM, Rifai N, Pfeffer MA, et al. Inflammation, pravastatin, and the risk of coronary events after myocardial infarction in patients with average cholesterol levels. Cholesterol and Recurrent Events (CARE) Investigators. Circulation 1998;98:839–844.PubMedGoogle Scholar
  29. 29.
    Campbell B, Badrick T, Flatman R, Kanowski D. Limited clinical utility of high-sensitivity plasma Creactive protein assays. Ann Clin Biochem 2002;39:85–88.CrossRefPubMedGoogle Scholar
  30. 30.
    Ridker PM, Cook N. Clinical usefulness of very high and very low levels of C-reactive protein across the full range of Framingham Risk Scores. Circulation 2004;109:1955–1959.CrossRefPubMedGoogle Scholar
  31. 31.
    Weight LM, Alexander D, Jacobs P. Strenuous exercise: analogous to the acute-phase response? Clin Sci (Lond) 1991;81:677–683.Google Scholar
  32. 32.
    Church TS, Barlow CE, Earnest CP, Kampert JB, Priest EL, Blair SN. Associations between cardiorespiratory fitness and C-reactive protein in men. Arterioscler Thromb Vasc Biol 2002;22:1869–1876.CrossRefPubMedGoogle Scholar
  33. 33.
    Ford ES. Body mass index, diabetes, and C-reactive protein among U.S. adults. Diabetes Care 1999;22: 1971–1977.CrossRefPubMedGoogle Scholar
  34. 34.
    Visser M, Bouter LM, McQuillan GM, Wener MH, Harris TB. Elevated C-reactive protein levels in overweight and obese adults. JAMA 1999;282:2131–2135.CrossRefPubMedGoogle Scholar
  35. 35.
    Tchernof A, Nolan A, Sites CK, Ades PA, Poehlman ET. Weight loss reduces C-reactive protein levels in obese postmenopausal women. Circulation 2002;105:564–569.CrossRefPubMedGoogle Scholar
  36. 36.
    Ziccardi P, Nappo F, Giugliano G, et al. Reduction of inflammatory cytokine concentrations and improvement of endothelial functions in obese women after weight loss over one year. Circulation 2002;105:804–809.CrossRefPubMedGoogle Scholar
  37. 37.
    Tracy RP, Psaty BM, Macy E, et al. Lifetime smoking exposure affects the association of C-reactive protein with cardiovascular disease risk factors and subclinical disease in healthy elderly subjects. Arterioscler Thromb Vasc Biol 1997;17:2167–2176.PubMedGoogle Scholar
  38. 38.
    Bermudez EA, Rifai N, Buring JE, Manson JE, Ridker PM. Relation between markers of systemic vascular inflammation and smoking in women. Am J Cardiol 2002;89:1117–1119.CrossRefPubMedGoogle Scholar
  39. 39.
    Ridker PM, Cushman M, Stampfer MJ, Tracy RP, Hennekens CH. Inflammation, aspirin, and the risk of cardiovascular disease in apparently healthy men. N Engl J Med 1997;336:973–979.CrossRefPubMedGoogle Scholar
  40. 40.
    Albert MA, Glynn RJ, Ridker PM. Alcohol consumption and plasma concentration of C-reactive protein. Circulation 2003;107:443–447.CrossRefPubMedGoogle Scholar
  41. 41.
    Cushman M, Legault C, Barrett-Connor E, et al. Effect of postmenopausal hormones on inflammationsensitive proteins: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Study. Circulation 1999; 100:717–722.PubMedGoogle Scholar
  42. 42.
    Cushman M, Meilahn EN, Psaty BM, Kuller LH, Dobs AS, Tracy RP. Hormone replacement therapy, inflammation, and hemostasis in elderly women. Arterioscler Thromb Vasc Biol 1999;19:893–899.PubMedGoogle Scholar
  43. 43.
    Ridker PM, Hennekens CH, Rifai N, Buring JE, Manson JE. Hormone replacement therapy and increased plasma concentration of C-reactive protein. Circulation 1999;100:713–716.PubMedGoogle Scholar
  44. 44.
    Herrington DM, Brosnihan KB, Pusser BE, et al. Differential effects of E and droloxifene on C-reactive protein and other markers of inflammation in healthy postmenopausal women. J Clin Endocrinol Metab 2001;86:4216–4222.CrossRefPubMedGoogle Scholar
  45. 45.
    Ng MK, Liu PY, Williams AJ, et al. Prospective study of effect of androgens on serum inflammatory markers in men. Arterioscler Thromb Vasc Biol 2002;22:1136–1141.CrossRefPubMedGoogle Scholar
  46. 46.
    Ikonomidis I, Andreotti F, Economou E, Stefanadis C, Toutouzas P, Nihoyannopoulos P. Increased proinflammatory cytokines in patients with chronic stable angina and their reduction by aspirin. Circulation 1999;100:793–798.PubMedGoogle Scholar
  47. 47.
    Feng D, Tracy RP, Lipinska I, Murillo J, McKenna C, Tofler GH. Effect of short-term aspirin use on C-reactive protein. J Thromb Thrombolysis 2000;9:37–41.CrossRefPubMedGoogle Scholar
  48. 48.
    Feldman M, Jialal I, Devaraj S, Cryer B. Effects of low-dose aspirin on serum C-reactive protein and thromboxane ß2 concentrations: a placebo-controlled study using a highly sensitive C-reactive protein assay. J Am Coll Cardiol 2001;37:2036–2041.CrossRefPubMedGoogle Scholar
  49. 49.
    Ferroni P, Martini F, Cardarello CM, Gazzaniga PP, Davi G, Basili S. Enhanced interleukin-1beta in hypercholesterolemia: effects of simvastatin and low-dose aspirin. Circulation 2003;108:1673–1675.CrossRefPubMedGoogle Scholar
  50. 50.
    Ridker PM, Rifai N, Clearfield M, et al. Measurement of C-reactive protein for the targeting of statin therapy in the primary prevention of acute coronary events. N Engl J Med 2001;344:1959–1965.CrossRefPubMedGoogle Scholar
  51. 51.
    Jialal I, Stein D, Balis D, Grundy SM, Adams-Huet B, Devaraj S. Effect of hydroxymethyl glutaryl coenzyme a reductase inhibitor therapy on high sensitive C-reactive protein levels. Circulation 2001;103: 1933–1935.PubMedGoogle Scholar
  52. 52.
    Meier-Ewert HK, Ridker PM, Rifai N, Price N, Dinges DF, Mullington JM. Absence of diurnal variation of C-reactive protein concentrations in healthy human subjects. Clin Chem 2001;47:426–430.PubMedGoogle Scholar
  53. 53.
    Gudewill S, Pollmächer T, Vedder H, Schreiber W, Fassbender K, Holsboer F. Nocturnal plasma levels of cytokines in healthy men. Eur Arch Psychiatry Clin Neurosci 1992;242:53–56.CrossRefPubMedGoogle Scholar
  54. 54.
    Ledue TB, Rifai N. High sensitivity immunoassays for C-reactive protein: promises and pitfalls. Clin Chem Lab Med 2001;39:1171–1176.CrossRefPubMedGoogle Scholar
  55. 55.
    Roberts WL, Schwarz EL, Ayanian S, Rifai N. Performance characteristics of a point of care C-reactive protein assay. Clin Chim Acta 2001;314:255–259.CrossRefPubMedGoogle Scholar
  56. 56.
    Rothkrantz-Kos S, Schmitz MP, Bekers O, Menheere PP, van Dieijen-Visser MP. High-sensitivity Creactive protein methods examined. Clin Chem 2002;48:359–362.PubMedGoogle Scholar
  57. 57.
    Kebler A, Grunert C, Wood WC. The limitation and usefulness of C-reactive protein and elastase-a1 proteinase inhibitor complexes as analytes in the diagnosis and followup of sepsis in newborns and adults. Eur J Clin Chem Biochem 1994;32:365–368.Google Scholar
  58. 58.
    Wilkins J, Gallimore JR, Moore EG, Pepys MB. Rapid automated high sensitivity enzyme immunoassay of C-reactive protein. Clin Chem 1998;44:1358–1361.PubMedGoogle Scholar
  59. 59.
    Roberts WL, Moulton L, Law TC, et al. Evaluation of nine automated high-sensitivity C-reactive protein methods: implications for clinical and epidemiological applications. Part 2. Clin Chem 2001;47:418–425.PubMedGoogle Scholar
  60. 60.
    Roberts WL, Sedrick R, Moulton L, Spencer A, Rifai N. Evaluation of four automated high-sensitivity C-reactive protein methods: implications for clinical and epidemiological applications. Clin Chem 2000; 46:461–468.PubMedGoogle Scholar
  61. 61.
    Ridker PM, Glynn RJ, Hennekens CH. C-reactive protein adds to the predictive value of total and HDL cholesterol in determining risk of first myocardial infarction. Circulation 1998;97:2007–2011.PubMedGoogle Scholar
  62. 62.
    Ridker PM, Rifai N, Rose L, Buring JE, Cook NR. Comparison of C-reactive protein and low-density lipoprotein cholesterol levels in the prediction of first cardiovascular events. N Engl J Med 2002;347: 1557–1565.CrossRefPubMedGoogle Scholar

Copyright information

© Humana Press Inc., Totowa, NJ 2006

Authors and Affiliations

  • Nader Rifai
    • 1
    • 2
  1. 1.Children’s HospitalBoston
  2. 2.Harvard Medical SchoolBoston

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