Systemic lupus erythematosus laboratory tests
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Differentiating Systemic lupus erythematosus from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
Diagnosis
Antinuclear antibody (ANA) testing and anti-extractable nuclear antigen (anti-ENA) form the mainstay of serologic testing for SLE.Several techniques are used to detect ANAs.Clinically the most widely used method is indirect immunofluorescence.The pattern of fluorescence suggests the type of antibody present in the patient's serum.
ANA screening yields positive results in many connective tissue disorders and other autoimmune diseases, and may occur in normal individuals. Subtypes of antinuclear antibodies include anti-Smith and anti-double stranded DNA (dsDNA) antibodies (which are linked to SLE) and anti-histone antibodies (which are linked to drug-induced lupus). Anti-dsDNA antibodies are highly specific for SLE; they are present in 70% of cases, whereas they appear in only 0.5% of people without SLE.[1] The anti-dsDNA antibody titers also tend to reflect disease activity, although not in all cases.[1] Other ANA that may occur in SLE sufferers are anti-U1 RNP (which also appears in systemic sclerosis), SS-A (or anti-Ro) and SS-B (or anti-La; both of which are more common in Sjögren's syndrome). SS-A and SS-B confer a specific risk for heart conduction block in neonatal lupus.[2]
Other tests routinely performed in suspected SLE are complement system levels (low levels suggest consumption by the immune system), electrolytes and renal function (disturbed if the kidney is involved), liver enzymes, complete blood count and recently By proteomics, we can directly detect proteins as gene products as well as their alterations by post-translational modification and internal abscission which are characteristically observed in proteins.[3]
Previously, the lupus erythematosus (LE) cell test was not commonly used for diagnosis because those LE cells are only found in 50–75% of SLE cases, and are also found in some people with rheumatoid arthritis, scleroderma, and drug sensitivities. Because of this, the LE cell test is now performed only rarely and is mostly of historical significance.[4]
As a summary:
- Medical history
- Complete physical examination
- Laboratory tests:
- Complete blood count (CBC)
- Erythrocyte sedimentation rate (ESR)
- Urinalysis
- Blood chemistries
- Complement levels
- Antinuclear antibody test (ANA)
- Other autoantibody tests (anti-DNA, anti-Sm, anti-RNP, anti-Ro [SSA], anti-La [SSB])
- Anticardiolipin antibody test
References
- ↑ 1.0 1.1 Invalid
<ref>tag; no text was provided for refs namedrahman - ↑ Buyon JP, Clancy RM (2003). "Maternal autoantibodies and congenital heart block: mediators, markers, and therapeutic approach". Semin. Arthritis Rheum. 33 (3): 140–54. PMID 14671725. Unknown parameter
|month=ignored (help) - ↑ Iizuka N, Okamoto K, Hirohata S, Kato T (2009). "[Analysis of autoantigens in patients with systemic lupus erythematosus by using proteomic approach]". Nihon Rinsho Meneki Gakkai Kaishi (in Japanese). 32 (1): 43–7. PMID 19252377. Unknown parameter
|month=ignored (help) - ↑ NIM encyclopedic article on the LE cell test