Rheumatoid arthritis (RA) is an autoimmune disease that causes constant irritation of the joints. These autoimmune diseases are conditions that happen when the body’s tissues are erroneously attacked by their immune system due to antigen/antibody reactions. The immune system produces antibodies that are meant to fight infections or foreign bodies in our system. Patients with immune system deficiency have antibodies in their blood that attack their body tissues, which can cause inflammation.
Classic Rheumatoid arthritis features are joint tissue inflammation and inflammatory arthritis, the disease can also cause extra-articular inflammation and injury in other organs, but the targeted areas are the joints. Some experts referred to the disease as systemic illness and others called it a rheumatoid disease because it can affect other organs of the body.
Diagnosis of rheumatoid arthritis at the early stage is always not too easy to differentiate because the early signs and symptoms resemble those of many other diseases. There are batteries of the test carried out in the laboratory to diagnose rheumatoid arthritis but there is no one specific blood test or specific physical finding to confirm the diagnosis.
Before any diagnosis is carried out, your doctor ought to perform a physical examination on the patient. During the physical exam, your doctor will check for swelling in your joints or affected area. Also, redness and warmth will be checked in the affected area. All these physical examination results are what your doctor will use together with the diagnostic test results before confirming you to be a patient of rheumatoid arthritis. Rheumatoid arthritis is diagnosed by a rheumatologist based on a combination of the following:
- How the affected area/joints do look like? Any signs of inflammation?
- Any swelling in the affected area/joints or stiffness in the morning?
- Blood Test
- Image Test
Basic Blood Tests for The Diagnosis of Rheumatoid Arthritis
- Rheumatoid Factor (RF)
Rheumatoid factors are a group of proteins your body makes when your immune system attacks healthy tissue.
The normal range is 0-20 u/mL Values of RF higher than 20u/ml cannot be considered enough to diagnose RA because there are other reasons the RF level may be high in the body system. Conditions that can raise the levels of RF are other autoimmune diseases, certain chronic infections, diabetes, bacterial endocarditis, cancer, normal aging, vaccinations, and transfusions. About 70% of 90% of people with a high value have RA. At times people without RA can still have a rheumatoid factor.
2. Anti-Cyclic Citrullinated Pepride (Anti-CCP)
These are Proteins your body makes when there is inflammation. This test can be combined along with the RF test.
Normal Range: 20u/mL or less
High levels occur with people who have RA or those who are about to get it. Qualitative tests that show positive means there’s a 97% chance you have RA.
3. Erythrocyte Sedimentation Rate (ESR)
ESRis a test used to measure the rate of sedimentation of red blood cells per hour. The blood is allowed to stand in a tube, and the rate of sedimentation is measured.
Normal Range:
- Of men younger than 50 is 0-15 mm/h
- Of men older than 50 is 0-20 mm/h
- Of women younger than 50 is 0-20 mm/h
- Of women older than 50 is 0-30 mm/h
A high level of ESR shows inflammation while low levels are normal with healthy people. The high result does not point to any specific ailment, but only shows the signs of inflammation.
4. C-Reactive Protein (CRP)
This is a protein your liver makes when inflammation is present.
Normal range: Less than 10 milligrams per liter
This test is used to detect early signs of inflammation in your body. CRP levels always go up before you have the symptoms. A high level is an indication of inflammation, and the test is used to monitor the progress and treatment of diseases.
5. Antinuclear Antibody (ANA)
This test measures the presence of certain unusual antibodies in your blood called an antinuclear antibody. (ANA)
This test is measured by titration which is a reaction of two substances. A value of 1:40 dilution (or 1 part antibody to 40 parts solutions) is negative. Positive ANA result might be linked to autoimmune disorder while if negative, means you don’t have it.
6. HLA-B27
This is a protein that is situated on the surface of white blood cells.
There are cases where 8%-10% of people may have it, though most of them do not have the disease. HLA-B27 is gene-related, and it is linked to a condition called spondyloarthropathies (genetic marker). They are mostly found in joints and the places where ligaments and tendons attach to your bones.
7. Complete Blood Count: This full blood count is used to measure the basic components of the blood, and the test carried out are:-
- Red blood cells count, which carry oxygen from your lungs to your body. (Normal Range = 3.5 -5.6 million/mm3
- White blood cells count, which helps us fight infection. (Normal Range = 4 – 110000/mm3
- Hematocrit or PCV – Packed Cell Volume, helps to measure the percentage of red cells per volume in your system. (Normal Range = Men: 36% to 52%; women: 34 – 46%)
- Hemoglobin. This is a protein that helps your blood carry oxygen. (Normal Range = Men: 13.2 – 17.3g/dl)
- Platelets help in the area of blood clotting. It functions in case of a cut or injury that causes blood to flow out from the veins. (Normal Range = 150 – 450000/mm3 )
8. Creatine Kinase (CK)
This test measures the levels of the muscle enzyme creatine phosphokinase (CPK). Test results vary by age, gender, and race. A high level can be a sign of muscle inflammatory disease, and it can also show an increase in case of trauma or any muscle-related malfunctioning.
9. Citrulline Antibody Test
A positive result indicates the presence of RA. It is a useful diagnostic tool in establishing Rheumatoid arthritis cases of unexplained joint inflammation. The test can also be referred to as the anti-citrulline antibody test, or anti-cyclic citrullinated peptide antibody test. It is noted to be present in about 50%-75% of people with rheumatoid arthritis.
10. Cryoglobulins
This Protein clumps together when they’re exposed to a cold and when exposed to some degree of high temperature, they dissolve. There are three types of cryoglobulins which are:-
- Type I common in cancer cases.
- Type II usually occurs in people with hepatitis C.
- Type III is significant to an autoimmune disease.
A negative result shows there are no cryoglobulins in your blood while a positive result is a sign of RA.
11. Antineutrophil Cytoplasmic Antibodies (ANCA)
This is a protein that attacks the white blood cells in our body that helps us fight infections. Low white blood cells lead to low immunity in our system. A negative result shows no ANCA antibodies in your blood. Even if the titer is less than 1:20, it shows no significance.
Imaging Tests Used For The Diagnosis Of Rheumatoid Arthritis
There are three main types of RA imaging tests used in diagnosing and monitoring disease. These are:
- X-Ray
- Magnetic Resonance Imaging (MRI)
- Ultrasound
Depending on the doctor, a combination of these image tests will show a clearer picture in the diagnosis and treatment monitoring of rheumatoid arthritis.
X-Ray
X-rays are the standard radiographic imaging tests that is been used by doctors to assess and monitor patients with bone erosion occurring at the joints. X-rays show doctors where the erosion is occurring and how quickly it is progressing. But it only reveals after damage has been done and not at the onset of the disease.
MRI
This is a more advanced imaging test technique which involves a detailed look into the patient’s body. While X-rays most focus is at bones, MRIs detect abnormalities in the soft tissues like muscles, tendons and joint capsules.
MRI image test is better at detecting early signs of RA when compared to X-rays. It can also reveal the active inflammation occurring inside the joint capsule and detects the early signs of bone inflammation and destruction (prior to any permanent damage being made).
Ultrasound
As medical science progresses, tools used in diagnosis are also modernized or created. Ultrasound is a new diagnostic tool than x-ray and also helps in RA diagnostics and monitoring. Ultrasound functions using high-frequency sound waves which can translate pictures of the inside of the patient’s body and viewed on the screen. Unlike x-rays, ultrasounds do not emit any form of radiation.
Similar to MRI, ultrasound is better at detecting early signs of erosion caused by RA compared to x-rays. Ultrasound can also detect inflammation levels as this is important in monitoring disease progression. The use of ultrasound in monitoring joint deterioration in RA patients has become useful to doctors and now very common. However, x-rays still remain the basic standard tool that doctors use for monitoring RA disease progression.
An experienced doctor or rheumatologist should be able to combine both the battery of blood tests and the image test results in monitoring and control of Rheumatoid Arthritis disease.