In some cases RA factor is negative in lab test.
but they show the symptoms of rheumatoid arthritis how?
Just one addition - we recently published a post about blood test, what they mean and why they are not the only indicator of RA. You can read that here.
From what I understand, RA factor is not the cause of RA, just one possible blood indicator that is present in 70-80% of folk who have RA symptoms. On the other hand, there are people who test positive for RA factor and don't ever have symptoms (maybe never will or maybe later). The newer anti-CCP test is more accurate but still not 100%. This speaks to the complicated nature of RA. We still don't know all the causes and mechanics of it. Many researchers/doctors believe that there are actually many types or families of RA. That could be one reason why RA factor is negative in some people. The bottom line is that the sypmtoms are caused by inflammation brought on by your own immune system.
Many people around this RA Central forum, including myself, are RA factor negative (or seronegative). But we have all the symptoms. RA is a clinical diagnosis, not solely based on a blood test. It can be frustrating at times for those who are seronegative. You want a blood test to point to, sometimes people (even doctors) treat them differently, you question what's going on. But all it takes to remind me is to get a really bad flare and to inject myself once a week with medicine!
Just got back from a doc appointment and we talked about this very issue today. He said that it's well known that many patients don't show positive blood tests. But a diagnosis can be made without them. Even thought I'm "seronegative", he says I have RA. Seronegative arthritis, seronegative rheumatoid arthritis, or just rheumatoid arthritis, etc...call it what you will but it's treated all the same. When speaking to friends and family, I just call it RA now to avoid any confusion. He mentioned that "we know how to diagnose and treat RA, but we just don't know about all the underlying causes. The silver lining...seronegative cases tend to be less severe.
I was just recently tested for RA and Lupus and both came back negative. What other testing can they do if the negative RA test could still mean I have RA?
There are a limited number of blood tests that are related to RA. RA is a clinical diagnosis based primarily on symptoms. Check out the diagnosis criteria from the American College of Rheumatology that doctors use...
4 out of 7 symptoms and you're classified with RA and positive blood tests are only one of the 7.
If you have symptoms, don't let the sed negative test throw you off. It is a test of sedimentation. That means that your joints have eroded, and the little pieces of bone - called sediments because they are so small, and that is the diagnostic tool they use, along with classic symptoms.
In my case, I was exercising lots, drinking loads of water, and probably not a lot of build up initally of sediment - over a year before I was diagnosed without the blood test. Eventually, my sed rate sky rocketed, before I got everything under control. The sad thing is - I am sed negative again, because my disease is in remission, but I got a look at the results of my yearly xrays, and they said, "continued slow erosion of joints." So the rate is greatly slowed with the right meds, pain free, but in 20 or 30 years, should I live that long, the damage will continue to accumulate. One of the things they don't tell you. But I am happy not to be in pain, I exercise on a bike and with weights. play flute again, I am working part time on an M.Div, so life goes on.
If you are sed negative, and have terrible joint pain -fight, be aggressive, and don't take NO for an answer. Keep trying older rheumies, (they have learned from experience), and get on the meds you need.
I totally agree with Andrew. He is correct. There are several antibodies which are produced in a body with RA. The RF is only one of them. It just happened to be the first. The anti-CCP, discovered more recently, is more "accurate" because it corresponds better (90%) with the actual disease.
Hope you get treatment, if you need it, regardless of the RF.
Good luck, Kelly