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Arthritis: Blood Tests to Diagnose Arthritis
If your doctor suspects you have arthritis, he or she may have your blood drawn to determine which type of arthritis you have. In people with osteoarthritis, blood tests are not usually abnormal, but with other types of arthritis, including rheumatoid arthritis, certain tests will help your doctor decide which type you have.
This article reviews the different types of blood tests and markers used to diagnose arthritis and other inflammatory-related conditions.
What Blood Markers Are Used to Diagnose Rheumatoid Arthritis?
Rheumatoid factors are a variety of antibodies that are present in 70%-90% of people with rheumatoid arthritis (RA). A low level of rheumatoid factor can be found in people without RA or with other autoimmune disorders, however. In general, when no rheumatoid factor is present in someone with RA, the course of the disease is less severe. A new test for rheumatoid arthritis that measures levels of antibodies that bind citrulline modified proteins (anti-CCP) is more specific and tends to be only elevated in patients with rheumatoid arthritis or in patients about to develop rheumatoid arthritis. The presence of anti-CCP antibodies can be used to predict which patients will get more severe rheumatoid arthritis.
Are There Tests to Determine Inflammation?
Yes. The erythrocyte sedimentation rate (sed. rate or ESR) is an indication of the degree of inflammation in the body. It is actually a measurement of the speed with which red blood cells fall in a test tube of blood. When the inflammation in the blood goes up, these inflammatory substances attach to red blood cells and the cells fall faster. In healthy persons, the sed. rate is low and it climbs with inflammation. It doesn't point to any particular disease, but is a general indication of the amount of inflammation in the body. In lupus and polymyalgia rheumatica, the ESR often correlates with disease activity.
C-reactive protein (CRP) also indicates the amount of inflammation present. It is thought to be a better test than the sed. rate. In patients with rheumatoid arthritis, if the CRP is high, it suggests that there truly is significant inflammation or injury in the body.
Both CRP and ESR levels are used to monitor disease activity and how well someone is responding to treatment.
What Signs Indicate Connective Tissue Disorders like Lupus?
The ANA is a blood test that is used in the evaluation of possible lupus or other connective tissue disorders. When the ANA is positive, it indicates that someone may have an autoimmune disorder, but alone it can't make the diagnosis.
The ANA profile is a series of tests consisting of an ANA and other related antibodies. This may be done if the ANA is found to be positive or possibly at the same time as the ANA. This profile helps look for diseases such as Sjögren's syndrome, lupus and drug-induced lupus.
WebMD Medical Reference provided in collaboration with the Cleveland Clinic
Rheumatoid Arthritis Guide 
- Learn about Treatment for Moderate to Severe Rheumatoid Arthritis (RA)
- Is This RA Treatment Right For You?
- Some Fast Facts
Important Safety Information you should know about HUMIRA® (adalimumab).
Serious infections have happened in patients receiving HUMIRA. These infections include TB (tuberculosis) and infections caused by viruses, fungi, or bacteria that have spread throughout the body. Some patients have died from these infections.
Before starting HUMIRA:
Tell your doctor if you think you have an infection, are being treated for an infection, have signs of an infection (such as a fever, cough, or flu-like symptoms), have any open sores on your body, have warm, red, or painful skin, get a lot of infections or have infections that keep coming back, have or had hepatitis B infection, take the medicine Kineret (anakinra), have TB or have been in close contact with someone who has TB, have lived in an area where TB or histoplasmosis is common, or were born in, lived in or traveled where there is more risk for getting TB. Your doctor should test you for TB before starting HUMIRA. If your doctor prescribes any medicine for the treatment of TB, you should start taking it before starting HUMIRA and take the full course of TB medicine prescribed.
Tell your doctor if you have any numbness or tingling, or have a disease that affects your nervous system such as multiple sclerosis or Guillain-Barré syndrome, have heart failure or other heart conditions, are scheduled for major surgery, are pregnant, become pregnant, plan to become pregnant or are breastfeeding. Tell your doctor if you are allergic to HUMIRA or any of its ingredients or are allergic to rubber or latex. The needle cover of the prefilled syringe and the pen contain dry natural rubber.
Also, tell your doctor if you have recently received or are scheduled for any vaccines. Except for live vaccines, patients may still receive vaccines while on HUMIRA. It is recommended that children with juvenile idiopathic arthritis be brought up to date with all immunizations prior to starting HUMIRA.
After starting HUMIRA:
Call your doctor right away if you get an infection, or any sign of an infection including a fever, feeling very tired, cough, flu-like symptoms, warm, red or painful skin or if you have any open sores on your body. HUMIRA can make you more likely to get infections or make any infection that you may have worse.
Possible side effects of HUMIRA:
Serious side effects, which sometimes lead to death, have happened in patients taking HUMIRA.
- Serious infections. These infections include TB (tuberculosis) and infections caused by viruses, fungi, or bacteria. Your doctor will examine you for TB and perform a test to see if you have TB. If your doctor feels that you are at risk for TB, you may be treated with medicine for TB before you begin treatment with HUMIRA and during treatment with HUMIRA. Even if your TB test is negative your doctor should carefully monitor you for TB infections while you are taking HUMIRA. Patients who had a negative TB skin test before receiving HUMIRA have developed active TB. Tell your doctor if you have any of the following symptoms while taking or after taking HUMIRA: cough, low-grade fever, weight loss, or loss of body fat and muscle.
- Certain types of cancer. There have been cases of certain kinds of cancer in patients taking HUMIRA or other TNF blockers. Patients with RA, especially more serious RA, may have a higher chance for getting a kind of cancer called lymphoma. Some patients receiving HUMIRA have developed types of cancer called non-melanoma skin cancer (basal cell cancer and squamous cell cancer of the skin), which are generally not life threatening if treated. Tell your doctor if you have a bump or open sore that doesn't heal.
- Allergic reactions. Signs of a serious allergic reaction include skin rash, a swollen face, or trouble breathing.
- Hepatitis B virus reactivation in patients that carry the virus in their blood. Tell your doctor if you have any of the following symptoms: feel unwell, poor appetite, fatigue, fever, rash or joint pain.
- Nervous system problems. Signs and symptoms include: numbness or tingling, problems with your vision, weakness in your arms or legs, and dizziness.
- Blood problems. Symptoms include a fever that does not go away, bruising or bleeding very easily, or looking very pale.
- New heart failure or worsening heart failure you already have. Symptoms include shortness of breath or swelling of your ankles or feet, or sudden weight gain.
- Immune reactions including a lupus-like syndrome. Symptoms include chest discomfort or pain that does not go away, shortness of breath, joint pain, or rash on your cheeks or arms that gets worse in the sun.
Call your doctor or get medical care right away if you develop any of the above symptoms. Your treatment with HUMIRA may be stopped.
Common side effects of HUMIRA are: injection site reactions (redness, rash, swelling, itching or bruising), upper respiratory infections (sinus infections), headaches, rash and nausea.
These are not all the side effects with HUMIRA. Ask your doctor or pharmacist for more information.
Information You Should Know About HUMIRA® (adalimumab).
HUMIRA is used to reduce the signs and symptoms of moderate to severe rheumatoid arthritis in adults, may prevent further damage to your bones and joints, and may help your ability to perform daily activities. HUMIRA can be used alone or with methotrexate or with certain other medicines. HUMIRA is used to reduce the signs and symptoms of moderate to severe polyarticular juvenile idiopathic arthritis in children 4 years of age and older. HUMIRA can be used alone or with methotrexate or with certain other medicines. HUMIRA is used to reduce the signs and symptoms of psoriatic arthritis in adults, may prevent further damage to your bones and joints, and may help your ability to perform daily activities. HUMIRA can be used alone or with certain other medicines. HUMIRA is used to reduce the signs and symptoms of ankylosing spondylitis in adults. HUMIRA is used to reduce the signs and symptoms of moderate to severe Crohn's disease in adults who have not responded well to conventional treatments. HUMIRA is also for these adults with moderate to severe Crohn's disease who have lost response or are unable to tolerate infliximab. HUMIRA is used to treat moderate to severe chronic (lasting a long time) plaque psoriasis in adults who are under the ongoing care of a physician, have the condition in many areas of their body and who may benefit from taking injections or pills (systemic therapy) or phototherapy (treatment using ultraviolet light alone or with pills).
HUMIRA is taken by injection.
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