In a first, researchers have found that fibromyalgia can reliably be detected in blood samples which could possibly lead to a simple and fast diagnosis.
In the study that appears in the Journal of Biological Chemistry, researchers from The Ohio State University report success in identifying biomarkers of fibromyalgia and differentiating these from a handful of other related diseases.
The discovery could be an important turning point in care of patients with a disease that is frequently misdiagnosed or undiagnosed, leaving them without proper care and advice on managing their chronic pain and fatigue, said lead researcher Kevin Hackshaw, a professor in Ohio State's College of Medicine and a rheumatologist at the university's Wexner Medical Center.
Identification of biomarkers of the disease--a "metabolic fingerprint" like that discovered in the new study--could also open up the possibility of targeted treatments, he said.
To diagnose fibromyalgia, doctors now rely on patient-reported information about a multitude of symptoms and a physical evaluation of a patient's pain, focusing on specific tender points, he said. However, there is no blood test - no clear-cut, easy-to-use tool to provide a quick answer.
"We found clear, reproducible metabolic patterns in the blood of dozens of patients with fibromyalgia. This brings us much closer to a blood test than we have ever been," Hackshaw said.
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"Though fibromyalgia is currently incurable and treatment is limited to exercise, education and antidepressants, an accurate diagnosis has many benefits," said Hackshaw.
"Most physicians nowadays don't question whether fibromyalgia is real, but there are still skeptics out there," said Hackshaw.
Many undiagnosed patients have prescribed opioids--strong, addictive painkillers that have not been shown to benefit people with the disease, he said.
"When you look at chronic pain clinics, about 40 percent of patients on opioids meet the diagnostic criteria for fibromyalgia. Fibromyalgia often gets worse, and certainly doesn't get better, with opioids."
The current study included 50 people with a fibromyalgia diagnosis, 29 with rheumatoid arthritis, and 19 others who have osteoarthritis and 23 with lupus.
Researchers examined blood samples from each participant using a technique called vibrational spectroscopy, which measures the energy level of molecules within the sample.
Scientists in Rodriguez-Saona's lab detected clear patterns that consistently set fibromyalgia patients' blood sample results apart from those with other, similar disorders.
First, the researchers analysed blood samples from participants whose disease status they knew, so they could develop a baseline pattern for each diagnosis. Then, using two types of spectroscopy, they evaluated the rest of the samples blindly, without knowing the participants' diagnoses, and accurately clustered every study participant into the appropriate disease category based on a molecular signature.
"These initial results are remarkable. If we can help speed diagnosis for these patients, their treatment will be better and they'll likely have better outlooks. There's nothing worse than being in a gray area where you don't know what disease you have," said Rodriguez-Saona.
Rodriguez-Saona said that for the next study, he'd like to examine 150 to 200 subjects per disease group to see if the findings of this research are replicable in a larger, more diverse population. Hackshaw said his goal is to have a test ready for widespread use within five years.
Fibromyalgia is the most common cause of chronic widespread pain in the United States, and disproportionately affects women. The US Centers for Disease Control and Prevention estimates that about two per cent of the population--around 4 million adults--has fibromyalgia. Other organizations estimate even higher numbers.
Eventually, this work could lead to the identification of a particular protein or acid - or combination of molecules that is linked to fibromyalgia, Rodriguez-Saona said.
"We can look back into some of these fingerprints and potentially identify some of the chemicals associated with the differences we are seeing," he said.
In addition to identifying fibromyalgia, the researchers also found evidence that the metabolic fingerprinting technique has the potential to determine the severity of fibromyalgia in an individual patient.
"This could lead to better, more directed treatment for patients," Hackshaw said.