Laboratory testing for the rheumatic diseases can allow for rapid diagnosis and appropriate management, while false-positive tests can lead to inappropriate management and unnecessary concern for the patient. An evaluation of laboratory testing for rheumatic illnesses is discussed, including the well-known acute phase proteins, the use of ANA in screening, and the newer antibodies which may potentially allow for an earlier diagnosis. A thorough history and examination are arguably the best screening tests. Clinicians should be judicious in their use of laboratory testing, and should only do so in an attempt to further refine the diagnosis.
* While laboratory testing can help with the diagnosis of rheumatic disease, overreliance on a lab result may lead the clinician to an incorrect diagnosis.
* Antinuclear antibodies are present in a number of connective tissue diseases; while nearly all patients with lupus are ANA-positive, the high number of false positives limits its utility as a screening test.
* New tests, such as the cyclic citrullinated protein antibody, may improve early identification of patients with rheumatoid arthritis, particularly those with a prognosis for a more aggressive disease.
1.Sox HC Jr, Liang MH. The erythrocyte sedimentation rate: guidelines for rational use. Ann Intern Med1986;104:515–523.
2.Jones SA, Novick D, Horiuchi S, et al. C-reactive protein: a physiologic activator of interleukin 6 receptor shedding. J Exp Med 1999;189:599–604.
3.Zouki C, Beauchamp M, Baron C, et al. Prevention of in vitro neutrophil adhesion to endothelial cells through shedding of L-selectin by C-reactive protein and peptides derived from C-reactive protein. J Clin Invest 1997;100:522–529.
4.Wener MH, Daum PR, McQuillan GM. The influence of age, sex, and race on the upper reference limit of serum C-reactive protein concentration. J Rheumatol 2000;27:2351–2359.
5.Morley JJ, Kushner I, et al. Serum C-reactive protein levels in disease. Ann N Y Acad Sci1982;389:406–418.
6.Amos RS, Crockson RA, Crockson AP, et al. Rheumatoid arthritis: C-reactive protein and erythrocyte sedimentation rate during initial treatment. BMJ 1978;1:1396.
7.Solomon DH, Kavanaugh AJ, Schur PH, et al. Evidenced-based guidelines for the use of immunologic tests: antinuclear antibody testing. Arthritis Rheum 2002;47:434–444.
8.Tan EM, Feltkamp TE, Smolen JS, et al. Range of antinuclear antibodies in “healthy” individuals.Arthritis Rheum 1997;40:1601–1611.
9.Kavanaugh AF, Solomon DH. Guidelines for immunologic laboratory testing in the rheumatic diseases: anti-DNA antibody tests. Arthritis Rheum 2002;47:546–555.
10.Schur PH, Sandson J. Immunologic factors and clinical activity in systemic lupus erythematosus. N Engl J Med 1968;278:533–538.
11.Ter Borg EJ, Horst G, Hummel EJ, et al. Measurement of increases in anti-double-stranded DNA antibody levels as a predictor of disease exacerbation in systemic lupus erythematosus. Arthritis Rheum 1990;33:364.
12.Swaak AJ, Groenwold J, Bronsveld W. Predictive value of complement profiles and anti-dsDNA in systemic lupus erythematosus. Ann Rheum Dis 1986;45:359–366.
13.Harley JB, Alexander EL, Bias WB, et al. Anti-Ro (SS-A) and anti-La (SS-B) in patients with Sjögren’s syndrome. Arthritis Rheum 1986;29:196–206.
14.Reveille JD, Solomon DH, American College of Rheumatology Ad Hoc Committee of Immunologic Testing Guidelines. Evidenced-based guidelines for the use of immunologic tests: anticentromere, Scl-70, and nucleolar antibodies. Arthritis Rheum 2003;49:399–412.
15.Okano Y, Steen VD, Medsger TA Jr. Autoantibody to U3 nucleolar ribonucleoprotein (fibrillarin) in patients with systemic sclerosis. Arthritis Rheum 1992;35:95–100.
16.Falkner D, Wilson J, Fertig N, et al. Studies of HLA-DR and DQ alleles in systemic sclerosis patients with autoantibodies to RNA polymerase and U3-RNP (fibrillarin). J Rheumatol 2000;27:1196–1202.
17.Kroot EJ, de Jong BA, van Leeuwen MA, et al. The prognostic value of anti-cyclic citrullinated peptide antibody in patients with recent-onset rheumatoid arthritis. Arthritis Rheum 2000;43:1831–1835.
18.Stone JH, Talor M, Stebbing J, et al. Test characteristics of immunofluorescence and ELISA tests in 856 consecutive patients with possible ANCA-associated conditions. Arthritis Care Res 2000;13:424–434.
19.Guillevin L, Durand-Gasselin B, Cevallos R, et al. Microscopic polyangiitis. Arthritis Rheum1999;42:421–430.
20.Woodworth TG, Abuelo JG, Austin HA III, et al. Severe glomerulonephritis with late emergence of classic Wegener’s granulomatosis: report of 4 cases and review of the literature. Medicine (Baltimore)1987;66:181–191.
21.Hauschild S, Scmitt WH, Csernok E, et al. ANCA in systemic vasculitides, collagen vascular diseases, rheumatic disorders and inflammatory bowel diseases. Adv Exp Med Biol 1993;336:245–251.