What blood laboratory tests are necessary to diagnose Systemic Lupus Erythematosus (SLE) and Multiple Sclerosis (MS)?

From the Guidelines

To diagnose Systemic Lupus Erythematosus (SLE) and Multiple Sclerosis (MS), a combination of blood tests and other diagnostic methods are necessary, with the primary screening test for SLE being an antinuclear antibody (ANA) test, followed by more specific tests like anti-double-stranded DNA (anti-dsDNA), anti-Smith antibodies, and complement levels (C3 and C4), while for MS, blood tests are mainly used to rule out other conditions rather than confirm MS, and include tests for vitamin B12 deficiency, thyroid function, and inflammatory markers like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 1.

Diagnosis of SLE

For SLE, the following blood tests are necessary:

• ANA test as the primary screening test
• Anti-dsDNA test using a double-screening strategy with a last-generation SPA as the first step and CLIFT as the confirmation test 1
• Anti-Smith antibodies
• Complement levels (C3 and C4)
• Complete blood count (CBC) to check for anemia, low white blood cell count, or low platelet count

Diagnosis of MS

For MS, the following blood tests are necessary:

• Tests to rule out other conditions, such as:
  • Vitamin B12 deficiency
  • Thyroid function
  • Inflammatory markers like ESR and CRP
• Note that MS diagnosis requires clinical evaluation, imaging studies like MRI, and sometimes additional procedures like lumbar puncture or tissue biopsy, as blood tests alone are not sufficient for diagnosis 1

Important Considerations

• Neither SLE nor MS can be diagnosed by blood tests alone, and require a combination of clinical evaluation, imaging studies, and sometimes additional procedures like lumbar puncture or tissue biopsy 1
• The diagnosis of SLE and MS should be made based on the most recent and highest quality evidence, with consideration of the patient's clinical presentation and medical history 1

From the Research

Blood Laboratory Tests for SLE and MS

To diagnose Systemic Lupus Erythematosus (SLE) and Multiple Sclerosis (MS), several blood laboratory tests are necessary. The following tests are commonly used:

• Antinuclear antibody (ANA) test: This test is used to diagnose SLE, as a positive result can indicate the presence of autoantibodies [ 2 ].
• Anti-double stranded DNA (anti-dsDNA) test: This test is specific for SLE and can help distinguish it from other autoimmune disorders [ 3 ].
• Antiphospholipid antibody test: This test can help diagnose antiphospholipid syndrome, which is often associated with SLE [ 2 ].
• Erythrocyte sedimentation rate (ESR) test: This test measures inflammation in the body and can be elevated in SLE and MS [ 3 ].
• Cerebrospinal fluid (CSF) analysis: This test can help diagnose MS by detecting oligoclonal bands and measuring the IgG index [ 4 ].
• Aquaporin-4 (AQP4) antibody test: This test can help diagnose neuromyelitis optica, a condition that can be mistaken for MS [ 4 ].
• Myelin oligodendrocyte glycoprotein (MOG) antibody test: This test can help diagnose MOG-associated disorders, which can be mistaken for MS [ 4 ].

Additional Tests

Additional tests that may be used to diagnose SLE and MS include:

• Complete blood count (CBC) [ 5 ]
• Urinalysis [ 5 ]
• Blood panel [ 5 ]
• Anticardiolipin antibody test [ 5 ]
• Serum protein electrophoresis [ 5 ]
• Bone scanning [ 5 ]
• Skin biopsies with or without lupus band testing [ 5 ]

Limitations of Laboratory Tests

While laboratory tests can be helpful in diagnosing SLE and MS, they should not be relied upon exclusively [ 6 ]. A detailed medical history and physical examination are also essential for accurate diagnosis [ 6 ].