Blood Tests for Autoimmune Diseases

Autoimmune diseases are a group of conditions that occur when your immune system attacks healthy cells by mistake. Diagnosing autoimmune diseases can be a lengthy process: It can take more than five years to accurately diagnose an autoimmune disease. There is no one test that can diagnose all 80 types of autoimmune diseases. However, some blood tests can show whether there is an inflammatory process going on in a person's body, which is a characteristic of autoimmune diseases, and help point the way to the correct diagnosis. More specialized tests are available to pinpoint the exact disease.

autoimmune blood

krisanapong detraphiphat / Getty Images

C-Reactive Protein (CRP)

This test is used to measure the level of CRP, a protein that is produced by the liver and released into the bloodstream in response to inflammation. Changes in CRP levels can show active inflammation in the body caused by autoimmune diseases, a bacterial or fungal infection, or other chronic conditions, such as type 2 diabetes and osteoarthritis.

Interpretation of CRP levels is as follows:

  • Less than 0.3 mg/dL: Normal (This is the level seen in most healthy adults)
  • 0.3 to 1.0 mg/dL: Normal or minor elevation (This can be seen in obesity, pregnancy, depression, diabetes, common cold, gingivitis, periodontitis, sedentary lifestyle, smoking, and genetic polymorphisms)
  • 1.0 to 10.0 mg/dL: Moderate elevation (This indicates systemic inflammation such as in the case of rheumatoid arthritis, systemic lupus erythematosus (SLE), or other autoimmune diseases, malignancies, myocardial infarction, pancreatitis, bronchitis)
  • More than 10.0 mg/dL: Marked elevation (This signals acute bacterial infections, viral infections, systemic vasculitis, major trauma)
  • More than 50.0 mg/dL: Severe elevation (The cause may be acute bacterial infections)

Erythrocyte Sedimentation Rate (ESR)

The ESR test measures how quickly red blood cells (erythrocytes) collect at the bottom of a test tube that contains a blood sample. Normally, red blood cells settle relatively slowly. A faster-than-normal rate may indicate inflammation in the body. It could indicate an autoimmune disease, infections, cancer, chronic kidney disease, or other inflammatory conditions.

Your doctor may order this test if you have signs of an inflammatory disorder, such as headaches, fevers, weight loss, and joint stiffness. ESR can also be used to detect and monitor autoimmune diseases.

The normal ranges for ESR are:

  • 0 to 15 mm/hr for men under 50
  • 0 to 20 mm/hr for men above 50
  • 0 to 20 mm/hr for women under 50
  • 0 to 30 mm/hr for women above 50
  • 0 to 10 mm/hr for children
  • 0 to 2 mm/hr for infants

A very high ESR could indicate lupus, polymyalgia rheumatica, rheumatoid arthritis, among others.

Antinuclear Antibodies (ANA)

Antibodies are proteins that your immune system makes to fight foreign substances like viruses and bacteria. But an antinuclear antibody attacks your own healthy cells instead. It's called "antinuclear" because it targets the nucleus (center) of cells. Therefore, if an ANA test finds antinuclear antibodies in your blood, it may mean you have an autoimmune disorder. However, up to 15% of otherwise healthy people can have a positive low-titer ANA without any underlying autoimmune disease.

Primarily used for diagnosing SLE, this test measures the level of antibody, or titer, and is usually measured just as positive for the presence of antibodies or negative when no antibodies are detected. The presence of ANA does not confirm a diagnosis of SLE, but a lack of ANA makes that diagnosis much less likely. While ANA is used most often for a lupus diagnosis, these antibodies can sometimes also signal other systemic autoimmune disorders (cause inflammation throughout the body) like rheumatoid arthritis, scleroderma, or Sjögren's syndrome.

About 95% of those with SLE have a positive ANA test result.

Your doctor may order an ANA test if you have signs of an autoimmune disease such as fever, fatigue, a butterfly rash, muscle pain, and joint pain.

Ferritin

Ferritin is the protein that stores iron inside your cells until your body is ready to use it. Iron is required to make red blood cells, which carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organ function. Too little or too much iron in your system can cause serious health problems. Increased levels of ferritin (also known as hyperferritinemia) can be a sign of inflammation, infections, or malignancies, and are characteristics of conditions like Still's disease and hemophagocytic syndrome.

Normal ranges of ferritin include:

  • 20 to 250 ng/mL for adult men
  • 10 to 120 ng/mL for adult women, 18 to 39 years old
  • 12 to 263 ng/mL for women, 40 years old and over

Enzyme-linked Immunosorbent Assay (ELISA)

The ELISA test detects a number of specific antibodies or antigens in a blood sample. Your doctor will have an idea of what condition is causing your symptoms, then test your blood for specific antibodies that can be found in that disease. For example, in the case of rheumatoid arthritis, the ELISA test can be used to look at many markers, including IL-17, rheumatoid factor, and anti-CCP antibodies. Normal and abnormal ranges will vary based on the antigen being investigated. For some conditions, the detection of a particular antibody may be normal.

Rheumatoid Factor (RF)

The RF test checks for the presence of the rheumatoid factor, a protein produced by the immune system that can attack healthy joints, glands, or cells by mistake. It is usually used to diagnose rheumatoid arthritis, but it can also detect juvenile arthritis, lupus, certain infections like tuberculosis, some types of cancer such as leukemia, and other autoimmune disorders.

For RF, normal ranges are:

  • Less than 15 IU/mL
  • Less than 1:80 for titer levels

About 20% of people with rheumatoid arthritis have a small amount of or no rheumatoid factor in their blood. So even if your results are normal, your healthcare provider may order more tests like the anti-cyclic citrullinated peptide antibodies test to confirm or rule out rheumatoid arthritis.

Anti-cyclic Citrullinated Peptide (Anti-CCP) Antibodies

Anti-CCP antibodies, also called CCP antibodies, are a type of antibody called autoantibodies. Antibodies and autoantibodies are proteins made by the immune system. A CCP antibodies test measure the level of these autoantibodies. If CCP antibodies are found in your blood, it can be a sign of rheumatoid arthritis. 

Results are typically only listed as positive or negative. This test result is usually interpreted along with an RF test result:

  • Positive CCP antibodies and positive RF likely mean that someone has rheumatoid arthritis
  • Positive CCP antibodies and negative RF may mean someone is in the early stages of rheumatoid arthritis or will develop it in the future
  • Negative CCP antibodies and negative RF mean a person is less likely to have rheumatoid arthritis. Their provider may need to do more tests to help find out what is causing your symptoms.

CCP antibodies test results can also be reported in one of two ways:

  • Value, normal less than 15 IU/mL
  • Titer, normal less than 1:80 (1 to 80)

Normal value ranges may vary slightly among different laboratories.

Immunoglobulins

This test measures the amount of immunoglobulins, also known as antibodies, in your blood. It usually measures three specific types of immunoglobulins: igG, igM, and IgA. 

IgA is found in the linings of the respiratory tract and digestive system, as well as in saliva, tears, and breast milk. IgG is the most common antibody, and is found in the blood and other body fluids. It protects against bacterial and viral infections. This type of antibody can take time to form after an infection or immunization. IgM is found mainly in the blood and lymph fluid. It is the first antibody the body makes when it fights a new infection.

Examples of autoimmune diseases detected with this test include:

Routine Blood Tests

Routine blood work is also a big part of diagnosing autoimmune diseases. Some of the common blood tests your doctor may order include:

  • Basic metabolic panel or comprehensive metabolic panel: These tests measure your body's metabolism, detecting ranges of electrolytes and minerals in your blood. These measurements provide crucial data about how well different organs are functioning, and can signal problems with your pancreas, liver, heart, or kidneys. Abnormal results can signal problems like type 1 diabetes and autoimmune hepatitis.
  • Complete blood count: This test can detect abnormalities in red or white blood cells or clotting problems. Abnormal blood cell counts are common in diseases like SLE.
  • Coagulation studies like activated partial thromboplastin time and prothrombin time: These tests check the ability of your blood to clot, and can help detect disorders like antiphospholipid syndrome.

There are several other more routine tests that can detect inflammation, but abnormal levels in these tests may not necessarily be a sign of autoimmune disease, including:

  • Fibrinogen: 200 to 400 mg/dL
  • Haptoglobin: 410 to 1,650 mg/L
  • Albumin: 3.4 to 5.4 g/dL

Elevations in these tests can be a sign of tissue damage or inflammation caused by an autoimmune disease or other issues like infection or stress. 

Less Common Autoimmune Tests

To make a more accurate diagnosis, a number of blood tests target specific antibodies or autoimmune markers. Some specific antibody tests that your doctor may recommend include:

  • Anti-double stranded DNA (lupus)
  • Extractable nuclear antigen (lupus, Sjogren's systemic sclerosis, inflammatory myositis, mixed connective tissue disease)
  • Anti-signal recognition particle tests (inflammatory myositis)
  • Anti-neutrophil cytoplasmic antibody (granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, inflammatory bowel disease)
  • Complement complexes (lupus)
  • Cryoglobulins (Raynaud's syndrome)
  • Lupus anticoagulant, anti-cardiolipin or anti-phospholipid autoantibodies (lupus, antiphospholipid syndrome)

A Word From Verywell

Making a diagnosis for an autoimmune disease can be a long and frustrating process. You may need to take multiple blood tests, but these tests don't necessarily paint a complete picture. Talk with your doctor about any symptoms you have, even if you think they are not related to a particular condition. Every symptom is a clue that can help your doctor narrow their differential diagnosis.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Doghramji PP. Screening and Laboratory Diagnosis of Autoimmune Diseases Using Antinuclear Antibody Immunofluorescence Assay and Specific Autoantibody Testing. Updated 2016.

  2. MedlinePlus. Autoimmune disorders. Updated February 26, 2021.

  3. MedlinePlus. C-reactive protein (CRP) test. Updated December 3, 2020.

  4. MedlinePlus. Erythrocyte sedimentation rate (ESR). Updated July 31, 2020.

  5. Michigan Medicine. Sedimentation rate (sed rate). Updated August 5, 2020.

  6. MedlinePlus. ANA (antinuclear antibodies) test. Updated November 30, 2020.

  7. American College of Rheumatology. Antinuclear antibodies. Updated March 2019.

  8. Lupus Research Alliance. ANA testing.

  9. University of Rochester Medical Center. Ferritin (blood).

  10. University of California San Francisco. ELISA blood test.

  11. University of California San Francisco. Rheumatoid Factor (RF).

  12. MedlinePlus. Rheumatoid factor (RF) test. Updated December 3, 2020.

  13. MedlinePlus. CPP Antibody Test.

  14. Perez EE, Orange JS, Bonilla F, et al. Update on the use of immunoglobulin in human disease: a review of evidence. J Allergy Clin Immunol. 2017;139(3S):S1-S46. doi: 10.1016/j.jaci.2016.09.023.

  15. University of California San Francisco. Fibrinogen.

  16. University of California San Francisco. Haptoglobin.

  17. University of California San Francisco. Albumin blood (serum) test.