Symptom → lab tests
Which blood tests are used for unexplained weight loss?
Short answer
Losing weight without trying deserves a prompt, broad look: an overactive thyroid, diabetes, celiac disease and chronic inflammation are the common testable causes. The initial set is TSH with Free T4, hemoglobin A1c and glucose, a CBC, a comprehensive metabolic panel, CRP and a celiac screen — and a clinician visit alongside, because this symptom warrants one.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When should you see a clinician instead of ordering a test?
- Loss of more than about 5% of body weight in 6–12 months without trying — see a clinician
- Weight loss with night sweats, fever, a persistent cough, blood in stool or trouble swallowing — see a clinician promptly
Why these tests for unexplained weight loss?
Hyperthyroidism speeds metabolism (low TSH, high Free T4). New or uncontrolled diabetes causes weight loss with thirst and urination. Celiac disease and other malabsorption reduce nutrient uptake, and chronic inflammation or infection raises CRP and shifts the CBC.
Blood tests narrow the field quickly, but unexplained weight loss is one of the symptoms where a clinician should be involved early rather than after several rounds of self-ordered tests.
Which conditions do these tests help evaluate?
- 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.
- Celiac Disease — Celiac antibody testing and the markers used to screen for gluten-related disease.
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 $46.97 vs ordering the tests separately | Panel · 4 tests | $49.99 | Yes | 1–3 business days |
| Comprehensive Thyroid Test (TSH, Free T4, Free T3, Reverse T3, TPO)Saves $10.97 vs ordering the tests separately | Panel · 4 tests | $109.99 | No | 3–7 business days |
| Gut Health PanelSaves $83.96 vs ordering the tests separately | Panel · 5 tests | $129.99 | No | 3–7 business days |
| TSH Test (Thyroid Stimulating Hormone) | Test | $26.99 | No | 1–3 business days |
| Free T4 Test (Thyroxine) | Test | $23.99 | No | 1–3 business days |
| Hemoglobin A1c Test | Test | $21.99 | No | 2–4 business days |
| Fasting Glucose Test | Test | $24.99 | Yes | 1–3 business days |
| CBC with Differential Test | Test · 14 biomarkers | $21.99 | No | 1–3 business days |
| Comprehensive Metabolic Panel | Test · 14 biomarkers | $22.99 | Yes | 1–3 business days |
| C-Reactive Protein Test (CRP) | Test | $26.99 | No | 2–4 business days |
| Celiac Comprehensive Antibody Panel (tTG, DGP, EMA) | Test · 5 biomarkers | $124.99 | No | 3–7 business days |
Common questions
Should I order tests or see a doctor first?
Both is reasonable: order the baseline so results are ready for the visit, but book the visit. Unexplained weight loss is a symptom clinicians want to evaluate directly.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.