Acute Phase Proteins - Acute Phase Reactants

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Inflammation or infection not explained by other etiology

Laboratory Testing

Plasma proteins termed acute phase proteins or reactants are involved in the innate system response to inflammation, tissue injury, or malignancy. During inflammatory processes, the plasma concentration of these acute phase proteins increases or decreases by ≥50%.



  • Most acute phase reactants are synthesized in the hepatocytes
    • Not elevated in functional disturbances
    • Usually not elevated in stable chronic diseases
    • Strongly elevated in bacterial infections, juvenile arthritis, tumors, Crohn disease, surgery, polymyalgia rheumatica, systemic vasculitis, burns, fractures
    • Negligible elevation in arthralgia, myalgia, back pain

Acute Phase Proteins

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry


Choosing Wisely. An initiative of the ABIM Foundation. [Accessed: Jan 2017]

General References

Ceciliani F, Pocacqua V. The acute phase protein alpha1-acid glycoprotein: a model for altered glycosylation during diseases. Curr Protein Pept Sci. 2007; 8(1): 91-108. PubMed

Correale M, Brunetti ND, De Gennaro L, Di Biase M. Acute phase proteins in atherosclerosis (acute coronary syndrome). Cardiovasc Hematol Agents Med Chem. 2008; 6(4): 272-7. PubMed

Filip Z, Jan K, Vendula S, Jana KZ, Kamil M, Kamil K. Albumin and α1-acid glycoprotein: old acquaintances. Expert Opin Drug Metab Toxicol. 2013; 9(8): 943-54. PubMed

Malle E, Sodin-Semrl S, Kovacevic A. Serum amyloid A: an acute-phase protein involved in tumour pathogenesis. Cell Mol Life Sci. 2009; 66(1): 9-26. PubMed

Rehman AA, Ahsan H, Khan FH. α-2-Macroglobulin: a physiological guardian. J Cell Physiol. 2013; 228(8): 1665-75. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

La Pine TR, Joyner JL, Augustine NH, Kwak SD, Hill HR. Defective production of IL-18 and IL-12 by cord blood mononuclear cells influences the T helper-1 interferon gamma response to group B Streptococci. Pediatr Res. 2003; 54(2): 276-81. PubMed

Martins TB, Pasi BM, Litwin CM, Hill HR. Heterophile antibody interference in a multiplexed fluorescent microsphere immunoassay for quantitation of cytokines in human serum. Clin Diagn Lab Immunol. 2004; 11(2): 325-9. PubMed

Martins TB, Pasi BM, Pickering JW, Jaskowski TD, Litwin CM, Hill HR. Determination of cytokine responses using a multiplexed fluorescent microsphere immunoassay. Am J Clin Pathol. 2002; 118(3): 346-53. PubMed

Medical Reviewers

Last Update: November 2016