1) Your diagnosis is based exclusively on the results of a blood test.
In rheumatology, many diagnoses are supported by blood tests to check for various kinds of antibodies – proteins the immune system makes when it is mounting an attack and other markers for inflammation. But experts agree that blood-test results shouldn’t be the sole basis for a diagnosis.

In Muller’s case, for example, over the years, more than one doctor suspected RA and ordered blood tests to look for tell-tale rheumatoid factor and anti-CCP antibodies that sometimes signal the disease. But the tests all came back negative – as they do in up to 30 percent of people with RA.

Conversely, blood tests may be positive when no disease is present.

“I’d say that I see patients on a weekly basis who come to me and say, ‘I have lupus,’ because they tested positive for ANA,” says Robert Shaw, MD, a rheumatologist at the Carroll County Arthritis and Osteoporosis Center in Westminster, Md., referring to the test for anti-nuclear antibodies, which can indicate that the body is launching an immune attack on itself.

Antinuclear antibodies can show up for a number of reasons, not just lupus. Sometimes they can be associated with chronic infections, like sinusitis, and somewhere between 3 percent to 15 percent of healthy individuals carry ANAs with no ill effects.

Don’t hesitate to ask your doctor to detail the information on which a diagnosis is based. If he or she is mainly relying on test results, ask if there might be other options to consider. Don’t hesitate to ask for a second opinion – many doctors are open to collaboration with other physicians and medical professionals to help their patients.

2) Your doctor has prescribed a treatment, but it isn’t working.

Trial and error is often a necessary part of unmasking an illness, but always let your doctor know if a drug or therapy is not helping. “A very important diagnostic test is whether somebody responds to treatment the way you think they should,” says Gordon D. Schiff, MD, who researches patient safety at Brigham and Women’s Hospital in Boston.

However, if a treatment is not working, that doesn’t mean the diagnosis is wrong. While an antibiotic can usually clear up a bacterial infection, a given RA drug may work for some but not others. And frustratingly, disease-modifying anti-rheumatic drugs, which are the mainstays of treatment for inflammatory forms of arthritis, can take weeks or even months to start working.

“Just because you make the right diagnosis, doesn’t mean everybody responds,” Dr. Goldenberg cautions. “And some people’s pain may be multifactorial.”

Two diseases, osteoarthritis (OA) and RA, for example, may be at work, with each needing a different treatment.

This is where communication with your doctor is key. Before you start on any new treatment, ask what to expect and establish a time frame for seeing results.

If you aren’t getting better as quickly as you should, that’s the time to go back to your doctor for a medication adjustment, or if you feel the diagnosis just isn’t a good fit, it may be time to make an appointment for a second opinion.