Symptom → lab tests
What blood tests help explain dry skin, acne and rashes?
Short answer
Persistent skin changes sometimes have a systemic cause blood tests can find: dry, coarse skin with hypothyroidism; adult acne with androgen excess or PCOS; itching with liver, kidney or iron problems; and slow healing with high blood sugar or low zinc. TSH, a metabolic panel, ferritin, vitamin D, zinc, A1c and — for acne — androgens are the usual checks.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When should you see a clinician instead of ordering a test?
- A rapidly spreading rash, blistering, or a rash with fever or facial swelling — seek care immediately
- A new or changing mole, or a sore that doesn't heal — see a dermatologist
Why these tests for skin problems?
The skin reflects thyroid status, hormones, nutrition and organ function. TSH covers thyroid causes; the CMP covers liver and kidney causes of itching; ferritin catches iron deficiency (a cause of itch and hair changes); vitamin D and zinc are common deficiencies that affect healing; A1c screens for diabetes in acne or recurrent infections; testosterone and DHEA-S evaluate hormonal acne.
Which conditions do these tests help evaluate?
- Thyroid Problems — TSH, Free T4/T3 and antibodies to evaluate an under- or over-active thyroid.
- PCOS — Androgens, LH/FSH, insulin and thyroid markers to investigate PCOS.
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 |
|---|---|---|---|---|
| Vitamin & Mineral Deficiency PanelSaves $106.92 vs ordering the tests separately | Panel · 9 tests | $189.99 | No | 3–5 business days |
| Complete Thyroid PanelSaves $10.97 vs ordering the tests separately | Panel · 4 tests | $109.99 | No | 3–7 business days |
| Women's Hormone PanelSaves $129.90 vs ordering the tests separately | Panel · 11 tests | $239.99 | No | 3–5 business days |
| TSH (Thyroid Stimulating Hormone) | Test | $26.99 | No | 1–3 business days |
| Comprehensive Metabolic Panel | Test · 14 biomarkers | $22.99 | Yes | 1–3 business days |
| Ferritin | Test | $24.99 | No | 1–3 business days |
| Vitamin D, 25-Hydroxy | Test | $41.99 | No | 1–3 business days |
| Zinc | Test | $26.99 | Yes | 3–6 business days |
| Hemoglobin A1c | Test | $21.99 | No | 2–4 business days |
| Testosterone, Free & Total | Test · 2 biomarkers | $54.99 | No | 3–5 business days |
| DHEA-Sulfate | Test | $32.99 | No | 1–3 business days |
Common questions
Can a blood test diagnose the cause of a rash?
Rarely on its own. Blood work finds systemic contributors (thyroid, iron, liver, blood sugar); most rashes need a clinician or dermatologist to look at them.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.