Differential & Workup (Rule-Outs + Baseline)
Targeted tests help exclude common mimics/contributors and establish baselines. Adapt to context and findings.
Baseline / Targeted Tests
First-visit order set
- CBC, CMP, TSH/Free T4
- Ferritin/iron studies, B12, Folate, Vitamin D
- CRP/ESR; ANA if autoimmune features
- HbA1c; Lipids as indicated
As indicated by history / exam
- Morning cortisol if adrenal concern
- Sleep evaluation if symptoms suggest OSA/PLMD
- Orthostatic testing (lying/standing; consider tilt when appropriate)
- Additional tests driven by history/exam
Common Mimics
- Anemia/iron deficiency
- Thyroid disease
- Primary sleep disorders (OSA/PLMD)
- Major depressive disorder (without PEM), anxiety with hyperventilation
- Autonomic disorders including POTS variants
- Autoimmune disease
- Medication side-effects
- Endocrine/metabolic conditions
- Infection sequelae and other post-viral syndromes
Consider targeted testing when:
- red flags, atypical course, or focal neuro findings emerge
- weight loss, fevers, or inflammatory features are present
- sleep-disordered breathing is suspected by history/bed partner
- orthostatic symptoms suggest autonomic involvement
For health professionals. Informational only — not medical advice. Based on IOM/NAM 2015 criteria and common clinical practices.
