Diagnosing Rheumatoid Arthritis

Published by Steve Hedberg on December 5, 2009 Under arthritis

bloodtestRheumatoid Arthritis is one of the most common types of arthritis among the elderly. Unfortunately many types of arthritis can be rather difficult to diagnose.

There are several common laboratory tests that can be preformed to diagnose rheumatoid arthritis, as well as using imaging technology, like x-rays, but the results vary from person to person. Often, the symptoms of the patient are much more useful to the doctor during diagnosis.

Preforming a Complete Blood Count

This is a type of blood test that involves the doctor checking the number of different blood cells in a small sample of blood. Blood is made up of three basic types of cells, with red blood cells primarily transporting oxygen, white blood cells being used to fight infection, and platelets helping the body to form clots when there is a cut or some sort of bleeding.

There are several reasons a doctor may order a complete blood count, but it is often to ensure that the patients medications are not causing any problems. Also, it can sometimes provide an indication that the patient could have rheumatoid arthritis.

For example, often those with rheumatoid arthritis will have a lower red blood cell count. If the white blood cell count is high, it means the body is fighting an infection, which could be the result of the inflammation that is caused by rheumatoid arthritis. The number of platelets can also provide an indication that the body may be fighting an infection.

However, in all cases, it is possible to have rheumatoid arthritis and completely normal blood counts or if the blood counts are off, it could be caused by another problem.

Checking C-Reactive Protein Levels

In the body, C-Reactive Protein is a substance that is created when the body is fighting inflammation. Much in the same way an elevated white blood cell count could indicate infection, an elevated level of C-Reactive Protein can be an indication of rheumatoid arthritis.

In people with advanced rheumatoid arthritis, C-Reactive Protein levels are very often increased, but this varies from person to person.

Checking the Rate of Erythrocyte Sedimentation

The Erythrocyte Sedimentation Rate(ESR,) which is often simply referred to as the sed rate, can provide an indication that there may be inflammation in the body. Specifically, it measures how quickly the red blood cells in a sample settle to the bottom of the storage container.

In someone with inflammation, such as that caused by rheumatoid arthritis, the sed rate is sometimes higher than normal. However, this only happens to a little over half of those with rheumatoid arthritis.

Evaluating the Rheumatoid Factor

Sometimes, there are some noticeable antibodies that may be present in those with rheumatoid arthritis. Antibodies are used by the body to fight infection. These antibodies are not commonly found in those without rheumatoid arthritis, but again only about 70% of those with rheumatoid arthritis will have these antibodies present in their blood stream. This means that 1 in 5 of those with rheumatoid arthritis will not have any of these antibodies present in the blood stream.

Antinuclear Antibodies

Autoantibodies are antibodies that merge with the nuclei of cells, which is why they are called antinuclear antibodies. These antibodies are most common in those with lupus, but can also be found in about a third of those with rheumatoid arthritis.


Analyzing a persons genetics, a process called genetic typing, involves checking a person’s genes for specific markers that are common in those with rheumatoid arthritis. If these markers are present, it means the person is at an increased risk for developing rheumatoid arthritis, but again it is not conclusive. In fact, about 20% of those with rheumatoid arthritis do not show any predisposed genetic patterns indicating they are at risk.

Preforming an Urinalysis

Urinalysis involves analyzing a person’s urine and checking the levels of certain proteins and sugar levels. Urinalysis is one of the most effective ways to determine whether someone has diabetes and can also provide hints that the body is fighting an infection. Typically, urinalysis is not used to detect rheumatoid arthritis, but is instead important for ensuring the medication is not negatively affecting the patient and checking for other diseases that might share similar symptoms.

Digital Imaging

There are many types of digital imaging, but the X-Ray is the most common. By analyzing a patients x-rays, it is sometimes possible to spot the early effects of rheumatoid arthritis on the soft tissues and spot bone density loss. In the early stages, this can be tricky, but in the advanced stages of rheumatoid arthritis, small holes can often be clearly seen.

MRIs and other types of scans, like ultrasounds, are also sometimes used to check for inflammation around the joints, which is not typically visible when looking at an X-Ray. Bone densitometry is also common, which involves checking the density of the bones. This does not test for rheumatoid arthritis, however, but is instead checking for osteoporosis, which can greatly compound the effects of arthritis.

Making the Diagnosis

Unfortunately, while there are a number of tests that can be used to diagnose arthritis, they are not always effective. For example, it is common for those with arthritis to have normal blood counts and no abnormal antibodies or proteins in their blood.

For this reason, the patients history and symptoms must always be taken into account and often provide a much clearer diagnosis. In many cases, the doctor is more concerned with ruling out problems that share similar symptoms to rheumatoid arthritis, but are easier to test for.

This is not to say that most professional rheumatologists have difficulty diagnosing rheumatoid arthritis, but simply that there is no single definitive test for the disease.

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