Medical experts still struggle to understand the mechanisms behind this painful syndrome. A test involving blood markers may help solve the mystery.

Chronic fatigue syndrome can be a baffling disease.

It presents people with the condition a constellation of vague symptoms, but there’s no simple or quick way to diagnose it.

The condition has mystified medical experts for decades.

But new research is giving them hope that they are finally understanding the mechanisms behind this disease, and can soon develop a new way to diagnose it quickly.

An estimated 800,000 to 2.5 million Americans are believed to have chronic fatigue syndrome (CFS), or myalgic encephalomyelitis (ME).

However, only about 20 percent of those people have been diagnosed, according to the Centers for Disease Control and Prevention (CDC).

In the hope of finding a way to identify the disease quickly, researchers from Stanford University tested a variety of blood markers called cytokines from 192 patients with CFS, and compared them with cytokines taken from 392 healthy patients.

They published their findings in the Proceedings of the National Academy of Sciences last week.

Cytokines are proteins in the blood that can affect the immune system and inflammation.

The researchers tested 51 cytokines, and concluded that 17 had “a statistically significant” association with ME/CFS and its level of severity.

The more severe the disease’s symptoms, the higher the level of these cytokines.

Thirteen of the cytokines associated with the disease were proinflammatory, according to the study authors.

“There’s been a great deal of controversy and confusion surrounding ME/CFS — even whether it is an actual disease,” Mark Davis, PhD, professor of immunology and microbiology, and director of Stanford’s Institute for Immunity, Transplantation and Infection, said in a statement. “Our findings show clearly that it’s an inflammatory disease and provide a solid basis for a diagnostic blood test.”

The disease can affect anyone, but it is more common in people between the ages of 40 and 60. Women are more likely than men to develop the ailment, and it is more likely to occur in Caucasian people, according to the CDC.

Symptoms of ME/CFS include a lowered activity level, sleep problems, and a “post-exertional malaise,” where a person may “crash” after mental or physical exertion. People with ME/CFS also might have problems with memory or thinking, and a worsening of symptoms when they stand or sit up.

“I have seen the horrors of this disease, multiplied by hundreds of patients,” Dr. Jose Montoya, professor of infectious diseases at Stanford University, and lead author of the study, said in a statement. “It’s been observed and talked about for 35 years now, sometimes with the onus of being described as a psychological condition. But chronic fatigue syndrome is by no means a figment of the imagination. This is real.”

The disease also hits people financially, leading from $17 billion to $24 billion annually in medical bills and lost income, according to the CDC.

Dr. Sybil Marsh, a family medicine physician at University Hospitals Cleveland Medical Center, said the possibility of a diagnostic test could mean huge changes for patients when they first develop symptoms of the disease.

“It’s not something where you can immediately go in and think that you have it,” Marsh told Healthline.

She explained that people have to exhibit symptoms for at least six months before they can be diagnosed.

“All of the symptoms and disorders that are connected with it are also caused by something else,” she said.

Marsh said if patients could be diagnosed more quickly — within days or weeks of developing symptoms — they would not have to face months of uncertainty about their health.

Additionally, Marsh pointed out that understanding the mechanism behind the disease could mean someday finding a cure for the condition.

“Until we know what the mechanism is, we aren’t going to know how to treat it,” she said.

“Really, right now the treatment is around managing symptoms and coping with having this disorder,” Marsh explained.

Currently, people with ME/CFS are generally treated for symptoms such as depression, pain, or concentration problems, but there is no treatment that targets the syndrome itself.

“Often people become depressed because of all the things they have to lose and cut out of their life while they’re waiting for it to get better,” Marsh said.

For now, the Stanford researchers are hoping their study will propel the medical field toward solving the mystery of this disease.

They also said additional studies with larger study populations examined over longer periods of time will need to be done to verify their findings.