Symptom → lab tests
Which blood tests should you get for restless legs?
Short answer
Restless legs syndrome has one lab that changes management: ferritin. Brain iron is low in RLS, and guidelines recommend iron repletion when ferritin is below about 75 ng/mL even if hemoglobin is normal. A CBC, kidney function (metabolic panel), TSH, vitamin B12, folate, vitamin D and magnesium cover the other contributors. Kidney failure, pregnancy and several medications also cause or worsen RLS.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When should you see a clinician instead of ordering a test?
- Leg symptoms with numbness, weakness, or loss of bladder or bowel control — urgent evaluation
- Swelling, warmth or pain in one calf (possible clot)
- Restless legs that started after a new medication — antihistamines, antidepressants and anti-nausea drugs are common triggers; ask the prescriber before stopping
Why these tests for restless legs?
Iron is central: ferritin below ~75 ng/mL is associated with more severe RLS, and treating it improves symptoms — the transferrin saturation from an iron panel helps guide the decision. A CBC shows whether anemia has developed.
Kidney disease is a major secondary cause; a metabolic panel screens kidney function. Hypothyroidism, B12 and folate deficiency, and low vitamin D and magnesium are each associated with RLS or leg discomfort and are correctable.
A1c matters because diabetic nerve damage causes leg sensations that are treated differently from RLS.
Which conditions do these tests help evaluate?
- Anemia — CBC, iron studies, ferritin, B12 and folate to find the cause of fatigue and low energy.
- Insomnia & Poor Sleep — Cortisol, thyroid, vitamin D and metabolic markers tied to disrupted sleep.
- Diabetes & Blood Sugar — A1c, fasting glucose and insulin to screen for prediabetes and diabetes.
Which tests, and what do they cost?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Baseline Anemia PanelSaves $56.96 vs ordering the tests separately | Panel · 5 tests | $74.99 | Yes | 2–4 business days |
| Sleep Health PanelSaves $100.93 vs ordering the tests separately | Panel · 8 tests | $129.99 | Yes | 3–5 business days |
| Vitamin & Mineral Deficiency PanelSaves $106.92 vs ordering the tests separately | Panel · 9 tests | $189.99 | No | 3–5 business days |
| Ferritin | Test | $24.99 | No | 1–3 business days |
| Iron Panel (Iron, TIBC & Ferritin) | Test · 4 biomarkers | $32.99 | Yes | 2–5 business days |
| CBC with Differential | Test · 14 biomarkers | $21.99 | No | 1–3 business days |
| Comprehensive Metabolic Panel | Test · 14 biomarkers | $22.99 | Yes | 1–3 business days |
| TSH (Thyroid Stimulating Hormone) | Test | $26.99 | No | 1–3 business days |
| Vitamin B12 | Test | $25.99 | No | 2–4 business days |
| Folate (Vitamin B9) | Test | $32.99 | No | 2–4 business days |
| Vitamin D, 25-Hydroxy | Test | $41.99 | No | 1–3 business days |
| Magnesium | Test | $19.99 | No | 2–4 business days |
| Hemoglobin A1c | Test | $21.99 | No | 2–4 business days |
Common questions
What ferritin level is recommended for restless legs?
Guidelines suggest treating iron when ferritin is under 75 ng/mL (some use 50) and transferrin saturation is under 20–45%, even without anemia. That is well above the lab's 'normal' cutoff, which is why a normal CBC does not rule out iron as the cause.
Can a blood test diagnose restless legs syndrome?
No — RLS is diagnosed from the symptom pattern: an urge to move the legs, worse at rest and in the evening, relieved by movement. Labs find the reversible contributors, iron above all.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.