Tests/Biomarkers
Although there isn’t a test or lab marker to diagnose your fibromyalgia, there are research tools to document that your pain control system is not working. In addition, scientists are attempting to identify biomarkers for this disease. A few techniques are described below. As new methods are reported in the medical journals, we will report on them here.
Reduced Pain Threshold
Thresholds for pressure, cold, and heat pain for people with fibromyalgia are not just a little lower than healthy control subjects. The thresholds for fibromyalgia patients are half that of healthy people and brain imaging objectively confirms this phenomenon. Giving fibromyalgia patients a painful stimulus that is half the intensity as that of control subjects causes the same degree of brain activation in the pain processing areas as the controls. Patients can’t fake this finding, but brain imaging is expansive and there are other conditions in which pain thresholds are reduced.
Defective Pain Inhibitory Controls
The pain inhibitory control system operates on the basis that pain will lead to the inhibition of pain. In other words, if a person gets injured, their pain inhibitory system kicks in to pour out natural opioids to greatly reduce their pain until they get to the hospital. This same process (without the physical injury) is used to test the effectiveness of one’s pain inhibitory system, and it is a three-step process.
Step One: A person is subjected to a moderately intense painful stimulus in their right arm, and they are asked to rate their perceived level of pain (this is the test stimulus).
Step Two: The person is then subjected to a painful stimulus (such as putting their left arm in a bucket of ice-cold water). This process should activate the person’s pain inhibitory system to release natural opioids and reduce their perception of pain.
Step Three: After two minutes, the same test stimulus from the first step is applied to the right arm and the subject is asked to rate it again. If their pain inhibitory system responds at all, they will rate the test stimulus as less painful.
A study funded by AFSA shows that 40 percent of fibromyalgia patients do not have a reduction in pain after they are subjected to the painful stimulus in step two.1 In other words, they rate the test stimulus as being just as painful in step three as in step one (and some rate it as more painful). Does this mean that the other sixty percent of fibromyalgia patients have an effective pain control system? Of course not! If your pain control processes were effective, you would not be in so much pain. The point is, this objective test shows that the pain inhibitory controls are not working at all in 40 percent of people with fibromyalgia.
Infrared Blood Analyzer
A blood test that distinguishes fibromyalgia from other chronic, painful conditions would make an ideal biomarker. Although many abnormalities have been found in the blood,they don’t separate fibromyalgia patients from others with chronic illnesses. However, a recent study by Kevin Hackshaw, M.D., at the University of Texas in Austin, shows that a portable infrared analyzer can distinguish people with fibromyalgia from patients with rheumatoid arthritis, lupus, osteoarthritis, and chronic low back pain.2 The analyzer used a fancy statistical program and it identified fibromyalgia patients with an 85 percent accuracy. Various amino acids in the blood (especially those related to glutamate) were key for separating fibromyalgia from the other painful conditions.
The infrared analyzer developed by Hackshaw is a portable device and it was tested on 179 fibromyalgia patients, along with 158 controls who had other painful conditions. Further studies using more patients are needed, but a portable analyzer could be used as a handy device at pain clinics, rheumatology offices, and other medical centers.
If you are wondering how the preliminary data on Hackshaw’s infrared analyzer compares to the current diagnostic criteria for fibromyalgia, it’s just as accurate. Better yet, this device does not rely upon a patient’s “subjective” endorsement of widespread pain.
1. Potvin S, Marchand S. PAIN 157(8):1704-1710, 2016. Abstract of AFSA-funded Study
2. Nuguri SM, Hackshaw KV, et al. Molecules 29(2):413, 2024. Free Journal Report