From: Biology and therapy of fibromyalgia. Evidence-based biomarkers for fibromyalgia syndrome
Objective marker | Findings |
---|---|
Genetics | Polymorphisms in catecholamine o-methyl transferase have been noted in some ethnic groups but not others; dopamine 4 receptor findings have not been replicated or refuted as compared with other polymorphisms |
Tender point counts or index | Multiple studies suggesting utility. The tender point count and the tender point index may be influenced by cognitive and emotional aspects of pain, and therefore may be biased |
Pressure pain threshold | Multiple studies suggesting utility. The pressure pain threshold may be influenced by cognitive and emotional aspects of pain, which may be minimized by utilizing a random pressure paradigm |
Heat and cold pain threshold | Consistently different in patients versus control individuals but not shown to be correlated with changes in clinical pain |
Diminished diffuse noxious inhibitory controls | Four cross-sectional studies by different groups suggest utility. Needs further exploration with standardized methods, longitudinal studies |
Functional neural imaging | Multiple studies suggesting utility. May be influenced by cognitive aspects of pain. Longitudinal studies needed |
Event-related potentials | Reduced P300 amplitude has been noted in three cross-sectional studies by two different groups. Larger studies with standardized methods are necessary. Longitudinal studies needed |
Sleep logs and polysomnography | Confirm reports of hypersomnolence, but no changes are pathognomonic of or specific for fibromyalgia |
Actigraphy | Inconsistent measure of sleep quality. Report suggesting utility in measuring functional status. Larger, longitudinal studies needed |
Hypothalamic–pituitary–adrenal axis | Flattened diurnal cortisol noted in three of four cross-sectional studies by two of three groups. Need to explore influence of biopsychosocial factors. Longitudinal studies needed |
Autonomic reactivity | Lower heart rate variability noted in three cross-sectional studies by two different groups. May predispose to condition. Longitudinal studies needed |
Autoantibodies | Antiserotonin antibody noted to be increased in three cross-sectional studies by two different groups. |
 | Stringent controls necessary prior to determining utility. Longitudinal studies needed |
Neuropeptides | Substance P noted to be increased in cerebrospinal fluid in four cross-sectional studies by various groups. |
 | Potential nonspecific marker of chronic pain |
Biochemical and cytokines | Low tryptophan and elevated IL-8 noted. Longitudinal studies needed |
Muscle abnormalities | No clear and reproducible abnormality. Additional studies with standardized methods needed |