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{{Systemic lupus erythematosus}}
{{Systemic lupus erythematosus}}


{{CMG}}; {{AE}} {{RT}}
{{CMG}}; {{AE}} {{MIR}}


Diagnosis of lupus can be problematic. Making a correct diagnosis of lupus requires knowledge and awareness on the part of the doctor and good communication on the part of the patient.
== Overview ==
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include [[autoantibody]] elevation of [[ANA]], [[anti-dsDNA antibody]], [[anti-SM antibody]], and [[antiphospholipid antibodies]], and a decrease in [[complement]] levels. Nonspecific laboratory findings include mild [[pancytopenia]], elevated levels of [[creatinine]] and [[proteinuria]] due to [[renal failure]] (secondary to [[nephritis]]), elevated levels of [[ESR]] and [[C-reactive protein|CRP]] as [[Acute phase reactant|acute phase reactants]], decreased level of [[Complement|complements]], and positive [[Coombs test|direct Coombs test]].


An accurate medical history, physical examination and the results of laboratory tests help the doctor consider other diseases that may mimic lupus or determine if you truly have the disease.10
== Laboratory tests ==
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include [[autoantibody]] elevation of [[ANA]], [[anti-dsDNA antibody]], [[anti-SM antibody]] and [[antiphospholipid antibodies]]. However, decrease of [[complement]] levels is a common finding in SLE.<ref name="pmid2646863">{{cite journal |vauthors=Tan EM |title=Antinuclear antibodies: diagnostic markers for autoimmune diseases and probes for cell biology |journal=Adv. Immunol. |volume=44 |issue= |pages=93–151 |year=1989 |pmid=2646863 |doi= |url=}}</ref><ref name="pmid23316252">{{cite journal |vauthors=Willitzki A, Hiemann R, Peters V, Sack U, Schierack P, Rödiger S, Anderer U, Conrad K, Bogdanos DP, Reinhold D, Roggenbuck D |title=New platform technology for comprehensive serological diagnostics of autoimmune diseases |journal=Clin. Dev. Immunol. |volume=2012 |issue= |pages=284740 |year=2012 |pmid=23316252 |pmc=3536031 |doi=10.1155/2012/284740 |url=}}</ref><ref name="pmid24864270">{{cite journal |vauthors=Li J, Leng X, Li Z, Ye Z, Li C, Li X, Zhu P, Wang Z, Zheng Y, Li X, Zhang M, Tian XP, Li M, Zhao J, Zhang FC, Zhao Y, Zeng X |title=Chinese SLE treatment and research group registry: III. association of autoantibodies with clinical manifestations in Chinese patients with systemic lupus erythematosus |journal=J Immunol Res |volume=2014 |issue= |pages=809389 |year=2014 |pmid=24864270 |pmc=4017718 |doi=10.1155/2014/809389 |url=}}</ref><ref name="pmid25449682">{{cite journal |vauthors=Yaniv G, Twig G, Shor DB, Furer A, Sherer Y, Mozes O, Komisar O, Slonimsky E, Klang E, Lotan E, Welt M, Marai I, Shina A, Amital H, Shoenfeld Y |title=A volcanic explosion of autoantibodies in systemic lupus erythematosus: a diversity of 180 different antibodies found in SLE patients |journal=Autoimmun Rev |volume=14 |issue=1 |pages=75–9 |year=2015 |pmid=25449682 |doi=10.1016/j.autrev.2014.10.003 |url=}}</ref><ref name="pmid16420554">{{cite journal |vauthors=Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, Derksen RH, DE Groot PG, Koike T, Meroni PL, Reber G, Shoenfeld Y, Tincani A, Vlachoyiannopoulos PG, Krilis SA |title=International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS) |journal=J. Thromb. Haemost. |volume=4 |issue=2 |pages=295–306 |year=2006 |pmid=16420554 |doi=10.1111/j.1538-7836.2006.01753.x |url=}}</ref><ref name="pmid18075790">{{cite journal |vauthors=Truedsson L, Bengtsson AA, Sturfelt G |title=Complement deficiencies and systemic lupus erythematosus |journal=Autoimmunity |volume=40 |issue=8 |pages=560–6 |year=2007 |pmid=18075790 |doi=10.1080/08916930701510673 |url=}}</ref><ref name="pmid15593352">{{cite journal |vauthors=Benito-Garcia E, Schur PH, Lahita R |title=Guidelines for immunologic laboratory testing in the rheumatic diseases: anti-Sm and anti-RNP antibody tests |journal=Arthritis Rheum. |volume=51 |issue=6 |pages=1030–44 |year=2004 |pmid=15593352 |doi=10.1002/art.20836 |url=}}</ref>


The most useful tests to aid a diagnosis identify certain autoantibodies often present in the blood of people with lupus. For example, the antinuclear antibody (ANA) test is commonly used to look for autoantibodies that react against components of the nucleus of the body's cells.
=== Laboratory changes in SLE: ===


About 98% of people with lupus possess ANA, which can attack the nucleic material of your cells. However, there are a number of other causes of a positive ANA besides lupus, including infections and other autoimmune diseases.
Diagnostic tools for lupus include:
* Medical history
* Complete physical exam
* Laboratory tests including complete blood count (CBC), erythrocyte sedimentation rate (ESR), urinalysis, blood chemistries, complement levels, ANA and other autoantibody tests
* Skin biopsy
* Kidney biopsy.
=== Blood tests for lupus ===
Example of an ANA panel test.
In people with a positive ANA, more tests are usually performed to check for other antibodies that can help confirm a diagnosis.
Certain autoantibodies and substances in the blood can give information about which autoimmune disease, if any, is present. To check for other antibodies, doctors usually order an ANA panel, which checks for the following antibodies:17
* Anti-phospholipid
* Anti-double-stranded DNA
* Anti-Smith
* Anti-U1RNP
* Anti-Ro/SSA
* Anti-La/SSB.
1) Antiphospholipid antibodies (APLs)
APLs are a type of antibody directed against phospholipids. APLs are present in up to 60% of people with lupus.
A positive test is also used to help identify women with lupus that have certain risks that require preventive treatment and monitoring. Those risks include blood clots, miscarriage, or preterm birth.
2) Anti-double-stranded DNA antibody
The anti-double-stranded DNA antibody (anti-dsDNA) is a specific type of ANA antibody found in about 30% of people with lupus. The presence of anti-dsDNA antibodies often suggests a more serious form of lupus, such as lupus nephritis (kidney lupus).
3) Anti-Smith antibody
An antibody to Sm, a ribonucleoprotein found in the nucleus of a cell, is found 20% of people with lupus. Unlike anti-dsDNA, anti-Sm does not correlate with the presence of kidney lupus.
4) Anti-U1RNP antibody
Anti-U1RNP antibodies are commonly found along with anti-Sm antibodies in people with lupus. The incidence of anti-U1RNP antibodies in people with lupus is approximately 25%. Anti-U1RNP has been shown to be associated with features of scleroderma, including Raynaud's phenomenon. It has also been linked to other conditions, such as Jaccoud's arthropathy, a deformity of the hand caused by arthritis.
5) Anti-Ro/SSA and anti-La/SSB antibodies
Anti-Ro/SSA and anti-La/SSB are antibodies found mostly in people with lupus (30-40%) and primary Sjögren's syndrome. They are also commonly found in people with lupus who have tested negative for ANA.
Babies of mothers with anti-Ro and anti-La antibodies are at an increased risk of neonatal lupus, an uncommon condition that produces a temporary rash and can lead to congenital heart block. Therefore, women with lupus who wish to become pregnant should be tested for these antibodies.
6) Anti-histone antibodies
Antibodies to histones, proteins that help to lend structure to DNA, are usually found in people with drug-induced lupus, but they can also be found in people with SLE. However, they are not specific enough to lupus to be used to make a concrete diagnosis.
=== Serum (blood) complement test ===
A serum complement test measures the levels of proteins consumed during the inflammatory process. Low complement levels reflect that inflammation is taking place within the body. Variations in complement levels exist in different individuals simply due to genetic factors.
Some laboratories also include other antibodies in their panel, including antinucleoprotein or anticentromere.
=== Urine tests for lupus ===
Besides blood tests used to diagnose and monitor lupus, doctors use urine tests to diagnose and monitor the effects of lupus on the kidneys. These tests include the following:19
* Measurement of glomerular filtration rate and proteinuria: this test measures how effective the kidneys are at filtering the blood to eliminate waste products. It is conducted on urine collected over a 24-hour period
* Protein/creatinine ratio: this test is performed on a one-time urine sample. It measures for protein loss, an indicator of kidney function
* Urinalysis: urinalysis can be used in screening for kidney disease. The presence of protein, red blood cells, white blood cells and cellular casts may all indicate kidney disease.
Other laboratory tests are used to monitor the progress of the disease after diagnosis, and the effectiveness of medications include:18
* Erythrocyte sedimentation rate (ESR): a test that measures the amount of inflammation in your body
* C-reactive protein (CRP)/Westergren sedimentation rate: like the ESR, the CRP test measures inflammation. However, CRP usually changes more rapidly than ESR because it is made by the liver and secreted hours after the beginning of infection or inflammation
* Creatine phosphokinase (CPK): creatine is an enzyme (a protein that helps to elicit chemical changes in your body) found in your heart, brain, and skeletal muscles. When muscle tissue is damaged, CPK leaks into your blood. A high level of CPK usually indicates stress or injury to your heart or other muscles
* Coombs' test: the Coombs' test is used to detect antibodies that act against the surface of your red blood cells. The presence of these antibodies indicates a condition known as hemolytic anemia, in which your blood does not contain enough red blood cells because they are destroyed prematurely. An acquired form, autoimmune hemolytic anemia (AIHA), is present in about 10% of people with lupus and results from an immune system attack on your red blood cells.
X-rays and other imaging tests can help doctors see the organs affected by lupus.
A rheumatologist's diagnosis is considered the gold standard, with the American College of Rheumatology (ACR) using a standard classification scheme that requires 4 of 11 criteria for research definition. This system can sometimes fail to recognize or miss early and mild cases.
<nowiki>***</nowiki>
{| class="wikitable"
{| class="wikitable"
!
! style="background: #4479BA; color: #FFFFFF; " |<small><small>Exam type</small></small>
!
! style="background: #4479BA; color: #FFFFFF; " |Lab exam
!
! style="background: #4479BA; color: #FFFFFF; " |Result
!
! style="background: #4479BA; color: #FFFFFF; " |Clinical correlation
!
|-
|-
| rowspan="3" |General lab exams
| rowspan="4" |<small>Hematology</small>
|Complete blood count
| style="background: #DCDCDC; " |[[Complete blood count]]
|leukopenia
 
mild anemia
 
thrombocytopenia
|
|
* [[Leukopenia]]
* [[Lymphopenia]]
* Mild [[anemia]]
* [[Thrombocytopenia]]
|
|
* Non-specific
* May be related to constitutional symptoms
|-
|-
|serum creatinine
| style="background: #DCDCDC; " |[[Serum creatinine]]
|Elevated  
|Elevated  
|suggestive of renal dysfunction
|
|
* Suggestive of [[renal dysfunction]]
|-
| style="background: #DCDCDC; " |[[Amylase]]
| rowspan="2" |Elevated
| rowspan="2" |
* Acute [[pancreatitis]]
|-
|-
|Urinalysis with urine sediment
| style="background: #DCDCDC; " |[[Lipase]]
|hematuria, pyuria, proteinuria, and/or cellular casts
|-
|
| rowspan="2" |<small>Urine</small>
|
| style="background: #DCDCDC; " |[[Urinalysis]]
 
| rowspan="2" |
* [[Hematuria]]
* [[Pyuria]]
* [[Proteinuria]]
* Cellular casts
| rowspan="2" |
* Suggestive of [[renal dysfunction]]
|-
| style="background: #DCDCDC; " |Urine sediment
|-
|-
| rowspan="12" |Specefically lab exams for SLE diagnosis
| rowspan="13" |<small>Serology</small>
|ANA
| style="background: #DCDCDC; " |[[ANA]]
|Elevated
|
|
|positive in virtually all patients with SLE at some time in the course of their disease
* Positive in virtually all patients with SLE at some time in the course of their disease
|If the ANA is positive, one should test for other specific antibodies such as dsDNA, anti-Sm, Ro/SSA, La/SSB, and U1 ribonucleoprotein (RNP)
|-
|-
|Antiphospholipid antibodies
| style="background: #DCDCDC; " |Antiphospholipid antibodies
|lupus anticoagulant [LA], IgG and IgM anticardiolipin [aCL] antibodies; and IgG and IgM anti-beta2-glycoprotein [GP]
|
|
* [[Lupus anticoagulant]] (LA)
* [[IgG]] and [[IgM]] [[Anti-cardiolipin antibodies|anticardiolipin (aCL) antibodies]]
* [[IgG]] and [[IgM]] anti-beta2-glycoprotein (GP)
|
|
* Can be predictive of [[hematologic]] and [[Thromboembolic disease|thromboembolic]] involvement
|-
|-
|complement levels
| style="background: #DCDCDC; " |[[Complement]] levels
|C3 and C4 or CH50
|
|
* C3: Vary between varying between normal to slightly reduced
* C4: Reduced
* CH50: Reduced
|
|
* Impaired clearance of [[immune complexes]]
* Partial [[complement]] deficiency during disease flare ups
** Mostly due to [[complement]] over consumption
* [[Complement]] activity related to organ damage and [[Phagocytosis|auto-phagocytosis]]
|-
|-
|Erythrocyte sedimentation rate (ESR)
| style="background: #DCDCDC; " |[[Erythrocyte sedimentation rate|Erythrocyte sedimentation rate (ESR)]]
|Elevated
|
|
* Non-specific
|-
| style="background: #DCDCDC; " |[[C-reactive protein|C-reactive protein (CRP)]]
|Elevated
|
|
* Non-specific
|-
| style="background: #DCDCDC; " |Urine protein-to-creatinine ratio
|Elevated
|
|
* [[Lupus nephritis]]
|-
|-
|C-reactive protein (CRP)
| style="background: #DCDCDC; " |[[Anti-dsDNA antibody]]
|
|Elevated
|
|
|
* Highly specific for SLE
* As high as 70% of patients
|-
|-
|Urine protein-to-creatinine ratio
| style="background: #DCDCDC; " |[[Anti-SM antibody|Anti-SM antibodies]]
|
|Elevated
|
|
|
* Highly specific for SLE  
|-
* Positive in 30% of patients
|Anti-dsDNA
|highly specific for SLE


in 70% of patients
* Lack sensitivity
|
|
|-
|-
|anti-Sm antibodies  
| style="background: #DCDCDC; " |Anti-Ro/SSA antibodies
|highly specific for SLE
|Elevated
 
lack sensitivity
 
in 30% of patients
|
|
|
* Positive in 30% of patients
* More commonly associated with [[Sjögren’s syndrome]]
|-
|-
|Anti-Ro/SSA antibodies
| style="background: #DCDCDC; " |Anti-La/SSB antibodies
|in 30% of patients
|Elevated
more commonly associated with Sjögren’s syndrome
 
15593352
|
|
|
* Positive in 20% of patients
* More commonly associated with [[Sjögren's syndrome|Sjögren’s syndrome]]
|-
|-
|anti-La/SSB antibodies
| style="background: #DCDCDC; " |Anti-U1 RNP antibodies
|in 20% of patients
|Elevated
more commonly associated with Sjögren’s syndrome
15593352
|
|
|
* Positive in approximately 25% of patients with SLE
* Not specific, always present in patients with [[mixed connective tissue disease]] (MCTD)
|-
|-
|Anti-U1 RNP antibodies
| style="background: #DCDCDC; " |Antiribosomal P protein antibodies
|in approximately 25 percent of patients with SLE
|Elevated
Not specific, always present in patients with mixed connective tissue disease (MCTD)
 
15593352
|
|
|
* High specificity for SLE & low sensitivity for SLE
* Lack specificity for involvement of a particular organ system or disease manifestation
|-
|-
|Antiribosomal P protein antibodies
| style="background: #DCDCDC; " |[[Coombs test|Direct Coombs' test]]
|high specificity for SLE & low sensitivity for SLE
|Positive
lack specificity for involvement of a particular organ system or disease manifestation.
|
|
|
* Clinically important in the absence of other causes of [[hemolytic anemia]]
|}
|}


If the initial ANA test is negative, but the clinical suspicion of SLE is high, then additional antibody testing may still be appropriate. This is partly related to the differences in the sensitivity and specificity among the methods used to detect ANA.  
If the initial ANA test is negative, but the clinical suspicion of SLE is high, then additional antibody testing may still be appropriate. This is partly related to the differences in the sensitivity and specificity among the methods used to detect ANA.


Laboratory exams to distinguish SLE from other diseases
=== Laboratory exams to distinguish SLE from other diseases ===
{| class="wikitable"
{| class="wikitable"
!
! style="background: #4479BA; color: #FFFFFF; " |Test
!
! style="background: #4479BA; color: #FFFFFF; " |Interpretation
!
!
|-
|-
|anti-cyclic citrullinated peptide (CCP) antibodies
| style="background: #DCDCDC; " |Anti-cyclic citrullinated peptide (CCP) antibodies
|In patients with predominant arthralgias or arthritis may help exclude a diagnosis of rheumatoid arthritis (RA)
higher specificity for RA and may be more useful for distinguishing the arthritis associated with RA. (See "Biologic markers in the diagnosis and assessment of rheumatoid arthritis", section on 'Rheumatoid factors' and "Biologic markers in the diagnosis and assessment of rheumatoid arthritis
|
|
|
* In patients with predominant [[arthralgias]] or [[arthritis]] may help exclude a diagnosis of [[Rheumatoid arthritis|rheumatoid arthritis (RA)]]
* Higher specificity for [[RA]]
|-
|-
|Rheumatoid factor (RF)
| style="background: #DCDCDC; " |Rheumatoid factor (RF)
|less diagnostic utility since 20 to 30 percent of people with SLE have a positive RF
|
|
|
* Less diagnostic since only 20 to 30 percent of people with SLE have a positive [[RF]]
* Consider [[RA]]
|-
|-
| rowspan="4" |Serological studies for infection
| rowspan="4" style="background: #DCDCDC; " |Serological studies for infection
|serologic testing for human parvovirus B19
|In patients with a brief history (for example, less than six weeks) of predominant arthralgias or arthritis
|
|
* [[Serologic]] testing for [[Human parvovirus B19 infection|human parvovirus B19]]
** In patients with a brief history (for example, less than six weeks) of predominant [[arthralgias]] or [[arthritis]]
|-
|-
|serologic testing for hepatitis B virus (HBV) and hepatitis C virus (HCV)
|in patients with multisystemic clinical findings
|
|
* [[Serology|Serologic]] testing for [[Hepatitis|hepatitis B virus (HBV)]] and [[Hepatitis C virus|hepatitis C virus (HCV)]]
** In patients with multi-systemic clinical findings
|-
|-
|serologic studies for Borrelia
|n areas endemic for Lyme disease
|
|
* [[Serology|Serologic]] studies for [[borrelia]]
** Especially in areas endemic for [[lyme disease]]
|-
|-
|Testing for Epstein-Barr virus (EBV)
|
|
|
* Testing for [[Epstein-Barr virus|Epstein-Barr virus (EBV)]]
|-
|-
|Creatine kinase (CK)
| style="background: #DCDCDC; " |Creatine kinase (CK)
|may reflect myositis, which is relatively uncommon in patients with SLE.
|Myositis may also suggest an alternative diagnosis such as MCTD, polymyositis (PM), or dermatomyositis (DM).
|
|
* Can reflect [[myositis]] (relatively uncommon in patients with SLE)
* [[Myositis]] may also suggest an alternative diagnosis such as:
** [[Mixed connective tissue disease|MCTD]]
** [[Polymyositis|Polymyositis (PM)]]
** [[Dermatomyositis|Dermatomyositis (DM)]]
|}
|}


==Overview==
=== A more detailed look into auto-antibodies in SLE ===
 
{| class="wikitable"
==Laboratory Findings==
! style="background: #4479BA; color: #FFFFFF; " |Antibodies
 
! style="background: #4479BA; color: #FFFFFF; " |Prevalence
[[Antinuclear antibody]] (ANA) testing and anti-extractable nuclear antigen (anti-ENA) form the mainstay of [[Serology|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.
! style="background: #4479BA; color: #FFFFFF; " |Association with disease activity
 
! style="background: #4479BA; color: #FFFFFF; " |Pathogenesis involvement
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 [[LSm|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. The anti-dsDNA antibody [[titer]]s also tend to reflect disease activity, although not in all cases. Other ANA that may occur in SLE sufferers are [[U1 spliceosomal RNA|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.<ref name="pmid14671725">{{cite journal |author=Buyon JP, Clancy RM |title=Maternal autoantibodies and congenital heart block: mediators, markers, and therapeutic approach |journal=Semin. Arthritis Rheum. |volume=33 |issue=3 |pages=140–54 |year=2003 |month=December |pmid=14671725 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0049017203001598}}</ref>
|-
 
| style="background: #DCDCDC; " |[[ANA]]
Other tests routinely performed in suspected SLE are [[complement system]] levels (low levels suggest consumption by the immune system), [[electrolyte]]s and [[renal function]] (disturbed if the kidney is involved), [[Liver function test|liver enzyme]]s, [[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.<ref name="pmid19252377">{{cite journal |author=Iizuka N, Okamoto K, Hirohata S, Kato T |title=[Analysis of autoantigens in patients with systemic lupus erythematosus by using proteomic approach] |language=Japanese |journal=Nihon Rinsho Meneki Gakkai Kaishi |volume=32 |issue=1 |pages=43–7 |year=2009 |month=February |pmid=19252377 |doi= |url=http://joi.jlc.jst.go.jp/JST.JSTAGE/jsci/32.43?from=PubMed |issn=}}</ref>
|80
 
| -
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.<ref>[http://www.nlm.nih.gov/medlineplus/ency/article/003635.htm NIM encyclopedic article on the LE cell test]</ref>
|[[Cutaneous lupus erythematosus]]
 
|-
As a summary:
| style="background: #DCDCDC; " |dsDNA
 
|70
*Medical history
| -/+
*Complete physical examination
|[[Lupus nephritis]]
*Laboratory tests:
|-
:*[[Complete blood count]] ([[CBC]])
| style="background: #DCDCDC; " |Anti-Sm antibodies
:*[[Erythrocyte sedimentation rate]] ([[ESR]])
|30
:*Urinalysis
| -
:*Blood chemistries
|[[Renal]], [[Neurology|neurologic]], [[vasculitis]] and [[hematologic diseases]]
:*Complement levels
|-
:*[[Antinuclear antibody|Antinuclear antibody test]] ([[ANA]])
| style="background: #DCDCDC; " |snRNP (U1 RNP)
:*Other autoantibody tests (anti-DNA, anti-Sm, anti-RNP, anti-Ro [SSA], anti-La [SSB])
|30-40
:*[[Anticardiolipin antibody|Anticardiolipin antibody test]]
| -
*[[Skin biopsy]]
| -
*[[biopsy|Kidney biopsy]]
|-
| style="background: #DCDCDC; " |SSA/Ro
|30
| -
|[[Neonatal lupus]]
|-
| style="background: #DCDCDC; " |SSB/La
|20
| -
|[[Neonatal lupus]]
|-
| style="background: #DCDCDC; " |Antiribosomal P protein antibodies
|20
| -
|[[Neuropsychiatry|Neuro-psychiatric]] disease, [[liver disease]]
|-
| style="background: #DCDCDC; " |RF
|20
| -
| -
|}


==References==
==References==

Latest revision as of 19:55, 2 August 2017

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahshid Mir, M.D. [2]

Overview

Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include autoantibody elevation of ANA, anti-dsDNA antibody, anti-SM antibody, and antiphospholipid antibodies, and a decrease in complement levels. Nonspecific laboratory findings include mild pancytopenia, elevated levels of creatinine and proteinuria due to renal failure (secondary to nephritis), elevated levels of ESR and CRP as acute phase reactants, decreased level of complements, and positive direct Coombs test.

Laboratory tests

Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include autoantibody elevation of ANA, anti-dsDNA antibody, anti-SM antibody and antiphospholipid antibodies. However, decrease of complement levels is a common finding in SLE.[1][2][3][4][5][6][7]

Laboratory changes in SLE:

Exam type Lab exam Result Clinical correlation
Hematology Complete blood count
  • Non-specific
  • May be related to constitutional symptoms
Serum creatinine Elevated
Amylase Elevated
Lipase
Urine Urinalysis
Urine sediment
Serology ANA Elevated
  • Positive in virtually all patients with SLE at some time in the course of their disease
Antiphospholipid antibodies
Complement levels
  • C3: Vary between varying between normal to slightly reduced
  • C4: Reduced
  • CH50: Reduced
Erythrocyte sedimentation rate (ESR) Elevated
  • Non-specific
C-reactive protein (CRP) Elevated
  • Non-specific
Urine protein-to-creatinine ratio Elevated
Anti-dsDNA antibody Elevated
  • Highly specific for SLE
  • As high as 70% of patients
Anti-SM antibodies Elevated
  • Highly specific for SLE
  • Positive in 30% of patients
  • Lack sensitivity
Anti-Ro/SSA antibodies Elevated
Anti-La/SSB antibodies Elevated
Anti-U1 RNP antibodies Elevated
Antiribosomal P protein antibodies Elevated
  • High specificity for SLE & low sensitivity for SLE
  • Lack specificity for involvement of a particular organ system or disease manifestation
Direct Coombs' test Positive

If the initial ANA test is negative, but the clinical suspicion of SLE is high, then additional antibody testing may still be appropriate. This is partly related to the differences in the sensitivity and specificity among the methods used to detect ANA.

Laboratory exams to distinguish SLE from other diseases

Test Interpretation
Anti-cyclic citrullinated peptide (CCP) antibodies
Rheumatoid factor (RF)
  • Less diagnostic since only 20 to 30 percent of people with SLE have a positive RF
  • Consider RA
Serological studies for infection
Creatine kinase (CK)

A more detailed look into auto-antibodies in SLE

Antibodies Prevalence Association with disease activity Pathogenesis involvement
ANA 80 - Cutaneous lupus erythematosus
dsDNA 70 -/+ Lupus nephritis
Anti-Sm antibodies 30 - Renal, neurologic, vasculitis and hematologic diseases
snRNP (U1 RNP) 30-40 - -
SSA/Ro 30 - Neonatal lupus
SSB/La 20 - Neonatal lupus
Antiribosomal P protein antibodies 20 - Neuro-psychiatric disease, liver disease
RF 20 - -

References

  1. ↑ Tan EM (1989). "Antinuclear antibodies: diagnostic markers for autoimmune diseases and probes for cell biology". Adv. Immunol. 44: 93–151. PMID 2646863.
  2. ↑ Willitzki A, Hiemann R, Peters V, Sack U, Schierack P, Rödiger S, Anderer U, Conrad K, Bogdanos DP, Reinhold D, Roggenbuck D (2012). "New platform technology for comprehensive serological diagnostics of autoimmune diseases". Clin. Dev. Immunol. 2012: 284740. doi:10.1155/2012/284740. PMC 3536031. PMID 23316252.
  3. ↑ Li J, Leng X, Li Z, Ye Z, Li C, Li X, Zhu P, Wang Z, Zheng Y, Li X, Zhang M, Tian XP, Li M, Zhao J, Zhang FC, Zhao Y, Zeng X (2014). "Chinese SLE treatment and research group registry: III. association of autoantibodies with clinical manifestations in Chinese patients with systemic lupus erythematosus". J Immunol Res. 2014: 809389. doi:10.1155/2014/809389. PMC 4017718. PMID 24864270.
  4. ↑ Yaniv G, Twig G, Shor DB, Furer A, Sherer Y, Mozes O, Komisar O, Slonimsky E, Klang E, Lotan E, Welt M, Marai I, Shina A, Amital H, Shoenfeld Y (2015). "A volcanic explosion of autoantibodies in systemic lupus erythematosus: a diversity of 180 different antibodies found in SLE patients". Autoimmun Rev. 14 (1): 75–9. doi:10.1016/j.autrev.2014.10.003. PMID 25449682.
  5. ↑ Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, Derksen RH, DE Groot PG, Koike T, Meroni PL, Reber G, Shoenfeld Y, Tincani A, Vlachoyiannopoulos PG, Krilis SA (2006). "International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS)". J. Thromb. Haemost. 4 (2): 295–306. doi:10.1111/j.1538-7836.2006.01753.x. PMID 16420554.
  6. ↑ Truedsson L, Bengtsson AA, Sturfelt G (2007). "Complement deficiencies and systemic lupus erythematosus". Autoimmunity. 40 (8): 560–6. doi:10.1080/08916930701510673. PMID 18075790.
  7. ↑ Benito-Garcia E, Schur PH, Lahita R (2004). "Guidelines for immunologic laboratory testing in the rheumatic diseases: anti-Sm and anti-RNP antibody tests". Arthritis Rheum. 51 (6): 1030–44. doi:10.1002/art.20836. PMID 15593352.

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