Symptom → lab tests
What blood tests check for excessive thirst?
Short answer
Constant thirst with frequent urination is the textbook presentation of high blood sugar, so hemoglobin A1c and fasting glucose lead, with a comprehensive metabolic panel for sodium, calcium and kidney function and a urinalysis. High calcium and certain kidney and pituitary conditions also drive thirst and are caught by the same panel.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When should you see a clinician instead of ordering a test?
- Thirst with vomiting, abdominal pain, deep rapid breathing, fruity breath or confusion — emergency care (possible diabetic ketoacidosis)
- Thirst with very high urine output (many liters a day) — see a clinician promptly
Why these tests for excessive thirst?
Glucose spilling into urine pulls water out of the body and triggers thirst. Elevated calcium and impaired kidney concentrating ability do the same. Medications (diuretics, some psychiatric drugs), dry mouth from mouth breathing and simple under-hydration are the common non-lab explanations.
Which conditions do these tests help evaluate?
- 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 |
|---|---|---|---|---|
| Diabetes Screening PanelSaves $9.98 vs ordering the tests separately | Panel · 3 tests | $59.99 | Yes | 2–5 business days |
| Kidney Health PanelSaves $36.97 vs ordering the tests separately | Panel · 4 tests | $64.99 | Yes | 2–4 business days |
| Hemoglobin A1c | Test | $21.99 | No | 2–4 business days |
| Glucose, Fasting | Test | $24.99 | Yes | 1–3 business days |
| Comprehensive Metabolic Panel | Test · 14 biomarkers | $22.99 | Yes | 1–3 business days |
| Urinalysis, Complete | Test · 10 biomarkers | $17.99 | No | 1–3 business days |
Common questions
Do I need to fast?
Only for fasting glucose (8–12 hours). A1c, the metabolic panel and urinalysis can be done any time, though a morning draw covers all of them in one visit.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.