When you have rheumatoid arthritis (RA), blood tests can be an important element in both diagnosis and managing the disease. Recently, several new blood tests have been added to the rheumatology arsenal. One of these is the Vectra DA test.
1. Blood tests for RA
Rheumatologists usually use four blood tests in the diagnosis of RA. These blood tests are the Sedimentation rate (ESR), C-reactive protein (CRP), Rheumatoid Factor, and the anti-CCP. The ESR and the CRP, both inflammatory markers, are also used in the ongoing monitoring of RA to assess your level of inflammation. However, they do not exclusively measure RA inflammation. Results may be influenced by other issues, such as infection, or in some cases they might come back normal, despite the active flare up of rheumatoid arthritis
2. What is the Vectra DA test?
Vectra DA is a newer blood test developed by Crescendo Bioscience. It is used in people who have already been diagnosed with RA to assess their level of disease activity. It is not used as part of diagnosing RA. Certain medications, infections, or surgical procedures may affect your score. Tell your doctor if you’ve been sick or had a vaccination before getting the Vectra test.
3. What the Vectra test measures
The test measures 12 different proteins or bio-markers that have been associated with RA activity. As it measures a dozen markers, as opposed to measuring only two inflammatory markers such as ESR and CRP, it is much more accurate. It offers an objective and quantitative score beyond physical exam that can be used to assess how effectively DMARDs or Biologics are controlling RA.
4. What your score means
The results of the Vectra test is indicated in a score from 0-100. A score of 1-29 means low disease activity. Moderate levels are indicated by 30-44. A score of 45-100 indicates a high level of disease activity. People who have high levels of RA activity are at higher risk for joint damage and bone erosions than those with low or moderate scores. Knowing your risk can help you and your rheumatologist make decisions about treatment.
5. Vectra predicts joint damage
A Swedish study looked at the Vectra scores of people newly diagnosed with RA and the correlation to radiographic progression (i.e., joint damage visible on x-ray) one year later. Twenty-one percent of people who scored high at baseline had damage one year later, versus 2.9 percent of low and moderate scorers. This shows that Vectra can be an important tool in RA treatment.
6. Vectra complements physician care
The Vectra blood test should not be used in isolation. It is intended to complement the physical exam that your doctor performs, as well as your own assessment of how you’re doing. People who have had the Vectra test when flaring have reported feeling a sense of relief to have scientific proof that substantiates their own assessment that the RA has become more active.
7. Cost and availability
Vectra DA is only available in the US. At about $1,000, it’s quite expensive. It’s important to check if your insurance covers it before getting the test. There is financial assistance through Crescendo Bioscience, the creators of the Vectra DA. This is offered at different levels, depending on your income and your insurance coverage. Medicare fully covers you getting the test twice a year.
8. Should you get the Vectra test?
Rheumatologists differ in their use of this test. Some feel that it’s a valuable addition that can assign a specific value to the level of inflammation and therefore indicate exactly how treatment is working. Others say it’s only useful if it’s really high or very low. It is also helpful for physicians to differentiate the joint pain due to RA from other cause of pain such as fibromyalgia. Talk to your rheumatologist about the role Vectra may play in your treatment.
9. Other ways to measure RA activity
If the Vectra DA test is not available to you, there are other ways to discover if your RA is active. Blood tests, such as the CRP and ESR, and imaging tests that obtain more detail about inflammation, such as the MRI and an ultrasound. As well, a physical exam by your rheumatologist, and your report of how well or poorly you’re functioning are essential aspects of assessing your RA. Rheumatologists also use other disease activity scoring systems such as DAS-28, CDAI, SDIA and Rapid-3 scoring.