Juvenile Primary Fibromyalgia Syndrome Workup

Updated: Apr 23, 2020
  • Author: Eileen R Giardino, RN, MSN, PhD, ANP-BC, FNP-BC; Chief Editor: Lawrence K Jung, MD  more...
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Approach Considerations

The patient’s history and physical examination guide the laboratory workup for fibromyalgia syndrome (FMS). Because the presentation and diagnosis by exclusion of other physical problems are often confusing, children with FMS may be evaluated by numerous physicians who perform various batteries of tests. Studies may include laboratory tests, diagnostic imaging, and polysomnography.


Lab Studies

Most laboratory tests are expected to produce findings within the reference range when FMS is diagnosed. Studies to consider in a child presenting with a clinical picture consistent with fibromyalgia syndrome and expected findings are discussed below.

  • Complete blood count (CBC) - Findings are normal.

  • Erythrocyte sedimentation rate (ESR) - 15 mm/h.

  • Rheumatoid factor - Findings are negative.

  • C-reactive protein and antinuclear antibody (ANA) - Findings may be positive. However, because of the high incidence of ANA in the general population, ANA testing should be avoided unless the history and physical examination indicate features and abnormalities not found in FMS.

  • Serum prolactin - Findings are negative.

  • Serum electrolytes - levels are within the reference range.

  • Liver function tests - Results are normal.

  • Muscle enzymes - levels are within the reference range.

  • Purified protein derivative - Findings are negative.

  • Blood and urine cultures - Results are negative.

  • Thyroid function tests - Results are normal.

  • Serotonin, substance P growth hormone, and cortisol - Characteristic changes in serotonin, substance P growth hormone, and cortisol suggest autonomic and neuroendocrine system dysregulation.


Diagnostic Imaging

Plain radiography of the chest, ribs, and back reveals normal findings, as does ultrasonography of the abdomen, pelvis, and paravertebrae. Bone scanning also reveals normal findings, and the results of computed tomography (CT) scanning and magnetic resonance imaging (MRI) are typically normal as well.



Polysomnography, including periodic limb movement in sleep (PLMS) assessment, which is used to evaluate possible sleep disorders, reveals normal findings.