A 50 percent uptick in the past couple of months in applications for a diagnostic blood test called FM/a for fibromyalgia is largely due to a new clinical trial testing a tuberculosis vaccine for treating the condition, according to EpicGenetics, which developed the test.

The collaborative Massachusetts General Hospital Phase 2 trial is investigating the use of a generic vaccine called BCG, globally used to prevent tubercolosis, to treat and reverse fibromyalgia.

In September, the U.S. Food and Drug Administration approved the EpicGenetics-funded trial, which the company says has resulted in more requests for the FM/a test.

“I regularly hear from patients who are thankful for a test that legitimizes their disease and saves them time and money of the traditional ‘rule out’ method,” Bruce Gillis, MD, EpicGenetics’ CEO, said in a press release. “Patients are mobilizing because now, for the first time, there is hope. They have the chance of a treatment that does more than merely mask the symptoms. It actually addresses the disease of fibromyalgia.”

The 2012 federal approval of FM/a, the first blood test for fibromyalgia, led California-based EpicGenetics to expand its research into disease treatment. This, in turn, led the company to Massachusetts General Hospital and Denise Louise Faustman, whose area of research is autoimmune diseases. She found that BCG stimulates a protein called tumor necrosis factor (TNF), which helps fight these disorders.

Now that the FDA has approved the Phase 2 trial of BCG in fibromyalgia, 300 patients who test positive on the FM/a for the disease, will be enrolled. Half of the participants will get the vaccine, and the other half a placebo. Taking place at Massachusetts General, the study will include volunteers of all ages.

Following the trial, findings will be submitted to the FDA, which will confirm whether BCG decreases pain and increases overall function in patients. More information about the trial and eligibility is available here.

Now covered by Medicare and most insurance plans, the multi-biomarker-based test is available in most U.S. states as well as Canada, Mexico, Turkey, Europe, Central and South America, Hong Kong, Australia, and New Zealand.

Requiring less than an ounce of blood, the test examines immune system white blood chemokine and cytokine patterns. Fibromyalgia patients have a markedly abnormal protein pattern.

The blood test notwithstanding, many clinicians continue to use traditional diagnostic measures, including imaging studies to rule out other disorders and interviewing patients about symptoms.

Fibromyalgia, a common and complicated chronic pain disorder that can affect patients not only physically but mentally and socially, causes extensive body pain and tenderness. It affects up to 20 million U.S. residents, mostly female, and can occur in individuals of all ages.

For years, fibromyalgia was widely seen as an imaginary disorder, mostly because there was no diagnostic test and because it primarily affected women, EpicGenetics said.

The company also recently reported that 80 percent of what is likely thousands of teens younger than 19 were misdiagnosed with attention deficit hyperactivity disorder (ADHD) before being tested for fibromyalgia. To help address this, the company will offer the FM/a test to youths at half-price.