Systemic lupus erythematosus laboratory tests: Difference between revisions

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== Overview ==
== Overview ==
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include anemia, leukopenia or lymphopenia, elevated levels of ANA, anti-dsDNA, anti-SM and antiphospholipid, and decrease of complement levels.
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include auto-antibodies elevation of ANA, anti-dsDNA, anti-SM and antiphospholipid antibodies, and decrease of complement levels.


== Laboratory tests ==
== Laboratory tests ==
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include anemia, leukopenia or lymphopenia, elevated levels of ANA, anti-dsDNA, anti-SM and antiphospholipid, and decrease of complement levels.
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include auto-antibodies elevation of ANA, anti-dsDNA, anti-SM and antiphospholipid antibodies, and decrease of complement levels.
{| class="wikitable"
{| class="wikitable"
!
!
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* Thrombocytopenia
* Thrombocytopenia
| colspan="2" |
| colspan="2" |
* Non-specific
* May be related to constitutional symptoms
|-
|-
|Serum creatinine
|Serum creatinine
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* Cellular casts
* Cellular casts
| colspan="2" |
| colspan="2" |
* Suggestive of renal dysfunction
|-
|-
| rowspan="12" |Serology
| rowspan="12" |Serology
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* IgG and IgM anti-beta2-glycoprotein [GP]
* IgG and IgM anti-beta2-glycoprotein [GP]
| colspan="2" |
| colspan="2" |
* aPLs are a heterogenous group of autoantibodies which are directed against phospholipid-binding proteins
* Can be predictive of hematologic and thromboembolic involvement
|-
|-
|complement levels
|Complement levels
<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="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>
|
|
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|Elevated
|Elevated
| colspan="2" |
| colspan="2" |
* Non-specific
|-
|-
|C-reactive protein (CRP)
|C-reactive protein (CRP)
|Elevated
|Elevated
| colspan="2" |
| colspan="2" |
* Non-specific
|-
|-
|Urine protein-to-creatinine ratio
|Urine protein-to-creatinine ratio
|Elevated
|Elevated
| colspan="2" |
| colspan="2" |
* Lupus nephritis
|-
|-
|Anti-dsDNA
|Anti-dsDNA
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* In 70% of patients
* In 70% of patients
|-
|-
|anti-Sm antibodies  
|Anti-Sm antibodies  
|Elevated
|Elevated
| colspan="2" |
| colspan="2" |
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** Polymyositis (PM)
** Polymyositis (PM)
** Dermatomyositis (DM)
** Dermatomyositis (DM)
|}
=== A more detailed look into auto-antibodies in SLE ===
{| class="wikitable"
!Antibodies
!Prevalence
!Association with disease activity
!Pathogenesis involvement
|-
|ANA
|80
| -
|Cutaneous lupus erythematosus
|-
|dsDNA
|70
| -/+
|Lupus nephritis
|-
|Nucleosomes
|60
| +
|Lupus nephritis
|-
|Anti-Sm antibodies
|30
| -
|Renal, neurologic, vasculitis and hematologic disorders are more prevalent
|-
|snRNP (U1 RNP)
|30-40
| -
| -
|-
|SSA/Ro
|30
| -
|Neonatal lupus
|-
|SSB/La
|20
| -
|Neonatal lupus
|-
|Antiribosomal P protein antibodies
|20
| -
|Neuropsychiatri c symptoms, liver disease
|-
|RF
|20
| -
| -
|}
|}


Revision as of 21:22, 15 July 2017

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: {{MIR}

Overview

Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include auto-antibodies elevation of ANA, anti-dsDNA, anti-SM and antiphospholipid antibodies, and decrease of complement levels.

Laboratory tests

Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include auto-antibodies elevation of ANA, anti-dsDNA, anti-SM and antiphospholipid antibodies, and decrease of complement levels.

Lab exam result clinical correlation
Hematology Complete blood count
  • Leukopenia
  • Lymphopenia
  • Mild anemia
  • Thrombocytopenia
  • Non-specific
  • May be related to constitutional symptoms
Serum creatinine Elevated
  • Suggestive of renal dysfunction
Amylase-Lipase Elevated
  • Acute pancreatitis
Urine Urinalysis

Urine sediment

  • Hematuria
  • Pyuria
  • Proteinuria
  • Cellular casts
  • Suggestive of renal dysfunction
Serology ANA Elevated
  • Positive in virtually all patients with SLE at some time in the course of their disease
Antiphospholipid antibodies

[1]

  • Lupus anticoagulant [LA]
  • IgG and IgM anticardiolipin [aCL] antibodies
  • IgG and IgM anti-beta2-glycoprotein [GP]
  • Can be predictive of hematologic and thromboembolic involvement
Complement levels

[2]

  • C3: vary between varying between normal to slightly reduced
  • C4: reduced
  • CH50: reduced
  • Impaired clearance of immune complexes
  • Impaired handling of apoptotic cells
  • Aberrant tolerance induction or changes in cytokine regulation
  • During disease flares, the complement system is activated giving rise to partial deficiency or dysfunction due to consumption
  • Takes part in the inflammatory reaction in the diseases which lead to the tissue and organ damage
Erythrocyte sedimentation rate (ESR) Elevated
  • Non-specific
C-reactive protein (CRP) Elevated
  • Non-specific
Urine protein-to-creatinine ratio Elevated
  • Lupus nephritis
Anti-dsDNA Elevated
  • Highly specific for SLE
  • In 70% of patients
Anti-Sm antibodies Elevated
  • Highly specific for SLE
  • In 30% of patients
  • Lack sensitivity
Anti-Ro/SSA antibodies

[3]

Elevated
  • In 30% of patients
  • More commonly associated with Sjögren’s syndrome
anti-La/SSB antibodies

[3]

Elevated
  • In 20% of patients
  • More commonly associated with Sjögren’s syndrome
Anti-U1 RNP antibodies

[3]

Elevated
  • In approximately 25 percent of patients with SLE
  • Not specific, always present in patients with mixed connective tissue disease (MCTD)
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
  • 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.

Laboratory exams to distinguish SLE from other diseases

Test Interpretation
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
Rheumatoid factor (RF)
  • Less diagnostic since only 20 to 30 percent of people with SLE have a positive RF
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 hepatitis B virus (HBV) and hepatitis C virus (HCV)
    • In patients with multi-systemic clinical findings
  • Serologic studies for Borrelia
    • Especially in areas endemic for Lyme disease
  • Testing for Epstein-Barr virus (EBV)
Creatine kinase (CK)
  • Can reflect myositis (relatively uncommon in patients with SLE)
  • Myositis may also suggest an alternative diagnosis such as:
    • MCTD
    • Polymyositis (PM)
    • Dermatomyositis (DM)

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
Nucleosomes 60 + Lupus nephritis
Anti-Sm antibodies 30 - Renal, neurologic, vasculitis and hematologic disorders are more prevalent
snRNP (U1 RNP) 30-40 - -
SSA/Ro 30 - Neonatal lupus
SSB/La 20 - Neonatal lupus
Antiribosomal P protein antibodies 20 - Neuropsychiatri c symptoms, liver disease
RF 20 - -

References

  1. ↑ 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.
  2. ↑ Truedsson L, Bengtsson AA, Sturfelt G (2007). "Complement deficiencies and systemic lupus erythematosus". Autoimmunity. 40 (8): 560–6. doi:10.1080/08916930701510673. PMID 18075790.
  3. ↑ 3.0 3.1 3.2 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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