Symptom → lab tests
Which blood tests should you get for itching without a rash?
Short answer
Itching all over without a visible rash is the presentation where blood tests earn their keep: liver disease (bile-salt itch), kidney disease, iron deficiency, thyroid disorders, diabetes, and blood conditions such as polycythemia and lymphoma can all cause it. A comprehensive metabolic panel, CBC, ferritin, TSH and A1c cover the common ones. Itching with yellow skin, night sweats or weight loss needs a clinician promptly.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When should you see a clinician instead of ordering a test?
- Itching with yellow skin or eyes, dark urine or pale stools — see a clinician promptly
- Itching with night sweats, fever, unexplained weight loss or swollen lymph nodes
- Hives with lip or tongue swelling, wheeze or trouble breathing — call 911
- Itching in pregnancy, especially palms and soles, in the third trimester — same-week evaluation (cholestasis of pregnancy)
Why these tests for itchy skin without a rash?
A comprehensive metabolic panel checks liver enzymes, bilirubin and kidney function — cholestatic liver disease and advanced kidney disease are two well-recognized causes of generalized itch. A GGT or hepatic panel adds detail if liver values are abnormal.
Iron deficiency causes itch even without anemia, so ferritin is checked alongside a CBC; the CBC also screens for polycythemia (itch after warm showers) and abnormal white cells. TSH covers both hypo- and hyperthyroidism, which itch through different mechanisms.
A1c screens for diabetes, which dries and irritates skin; allergy-related itch is usually visible, but total IgE and tryptase are sometimes added when hives come and go.
Which conditions do these tests help evaluate?
- Fatty Liver — Liver enzymes, metabolic and lipid markers to assess fatty liver risk.
- Anemia — CBC, iron studies, ferritin, B12 and folate to find the cause of fatigue and low energy.
- Thyroid Problems — TSH, Free T4/T3 and antibodies to evaluate an under- or over-active thyroid.
- 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 |
|---|---|---|---|---|
| General Wellness PanelSaves $6.97 vs ordering the tests separately | Panel · 4 tests | $89.99 | Yes | 1–3 business days |
| Baseline Anemia PanelSaves $56.96 vs ordering the tests separately | Panel · 5 tests | $74.99 | Yes | 2–4 business days |
| Complete Thyroid PanelSaves $10.97 vs ordering the tests separately | Panel · 4 tests | $109.99 | No | 3–7 business days |
| Comprehensive Metabolic Panel | Test · 14 biomarkers | $22.99 | Yes | 1–3 business days |
| Liver Function Panel | Test · 7 biomarkers | $19.99 | No | 1–3 business days |
| CBC with Differential | Test · 14 biomarkers | $21.99 | No | 1–3 business days |
| Ferritin | Test | $24.99 | No | 1–3 business days |
| TSH (Thyroid Stimulating Hormone) | Test | $26.99 | No | 1–3 business days |
| Hemoglobin A1c | Test | $21.99 | No | 2–4 business days |
| GGT (Gamma-Glutamyl Transferase) | Test | $19.99 | No | 1–3 business days |
| Tryptase | Test | $71.99 | No | 3–5 business days |
Common questions
Why would I itch all over with no rash?
Generalized itch without a rash points inward: liver, kidney, iron, thyroid, diabetes, medications and, less commonly, blood disorders. Dry skin and aging skin are the everyday causes; labs are how the internal ones are excluded.
Which liver test shows itching?
There isn't one specific test; itch tracks with bile-acid buildup, so alkaline phosphatase, bilirubin and GGT on a hepatic panel are the relevant markers. Serum bile acids can be added by a clinician.
Can low iron cause itching?
Yes — iron deficiency is an under-recognized cause of generalized itch and can occur with a normal hemoglobin. Ferritin is the test; repletion usually resolves it within weeks.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.