--- title: Kidney Function Test (Cystatin C) Test type: test id: cystatin-c url: "https://www.test-well.com/tests/cystatin-c" price_usd: 36.99 lab_fee_usd: 6 all_in_usd: 42.99 cpt: 82610 category: Kidney & Urinary sample: Blood draw fasting_required: false results_in: "2–4 business days" labs: - Quest - Labcorp - BioReference orderable: true reviewed_at: 2026-09-14 order_url: "https://www.test-well.com/cart?add=cystatin-c&utm_source=ai_agent&utm_medium=markdown" --- # Kidney Function Test (Cystatin C) Test > Kidney Function Test (Cystatin C) measures Cystatin C and eGFR (Cystatin C-based) from a standard blood draw. At TestWell it costs $36.99 plus a $6 lab fee, needs no fasting, and results post in 2–4 business days. Physician-authorized with no doctor's visit or insurance needed; draw at Quest or Labcorp. ## Key facts | Fact | Value | | --- | --- | | Price | $36.99 + $6 lab processing fee per order ($42.99 all-in for this test alone) | | CPT code | 82610 | | Sample | Blood draw | | Fasting | Not required | | Results | 2–4 business days | | Labs | Quest Diagnostics, Labcorp, BioReference (NY & NJ) | | Biomarkers measured | 2 | | Physician authorization | Included — no doctor's visit, referral or insurance needed | | Payment | Card, HSA or FSA; cash-pay only (no insurance billing) | ## What does the Kidney Function Test (Cystatin C) test tell you? More accurate kidney function marker than creatinine — not affected by muscle mass or diet. Cystatin C is a protein produced at a constant rate by all cells in the body and filtered by the kidneys. Unlike creatinine, it's not significantly affected by muscle mass, diet, age, or gender, making it a more accurate marker of kidney function in many populations including the elderly, athletes, and those with very high or low muscle mass. The eGFR calculated from cystatin C is increasingly recommended as a complementary or alternative measure to creatinine-based eGFR. **Clinical use:** Measures cystatin C, a protein filtered by the kidneys at a constant rate, to estimate glomerular filtration rate (eGFR). Because cystatin C is not affected by muscle mass, diet, or age the way creatinine is, it provides a more accurate picture of kidney filtration — especially in people with low muscle mass, obesity, or early-stage kidney disease where creatinine may look falsely normal. ## Who should order it? People with diabetes, high blood pressure, or a family history of kidney disease; anyone who received a borderline creatinine result and wants confirmation; older adults or those with low muscle mass whose creatinine may underestimate kidney decline; and patients monitoring kidney health while on medications that stress the kidneys. ## Biomarkers measured - [Cystatin C](https://www.test-well.com/biomarkers/cystatin-c) - [eGFR (Cystatin C-based)](https://www.test-well.com/biomarkers/egfr-cystatin-c) ## Price by lab | Lab | Test price | All-in (with $6 fee) | Notes | | --- | --- | --- | --- | | Quest Diagnostics | $36.99 | $42.99 | Choose at checkout; walk-in patient service centers nationwide (not NY/NJ) | | Labcorp | $36.99 | $42.99 | Choose at checkout; walk-in patient service centers nationwide (not NY/NJ) | | BioReference (NY & NJ) | $22.99 | $28.99 | New York and New Jersey orders route here automatically | Rhode Island is not served. Prices are identical online and in the lab; no draw fee or physician fee is added. ## How much does a Kidney Function Test (Cystatin C) test cost? A Kidney Function Test (Cystatin C) test costs $36.99 at TestWell — $42.99 all-in when ordered alone, because the $6 lab processing fee is charged once per order, with no draw fee or physician fee added. Hospital outpatient labs typically bill around $180.00 self-pay for the same test, and often more. With insurance, what you pay depends on your deductible and your plan's negotiated rate; TestWell's price is fixed before the draw and is HSA/FSA-eligible. | Where you order | Price | One test, all-in | Notes | | --- | --- | --- | --- | | TestWell (drawn at Quest or Labcorp) | $36.99 | $42.99 | Includes the one $6 lab processing fee, charged once per order | | Hospital outpatient lab, self-pay (typical) | $180.00 | $180.00 | Reference figure; hospital charges vary widely by facility and are often higher | Lab test codes: Quest test code 94588 · Labcorp test no. 121265 · BioReference code J013-4. ## How do you prepare? No fasting required. ## Related conditions - Chronic kidney disease (N18.9) - Acute kidney injury (N17.9) - Type 2 diabetes with diabetic chronic kidney disease (E11.22) - Hypertensive chronic kidney disease (I12.9) ## Common questions about the Kidney Function Test (Cystatin C) test ### How much does a cystatin C test cost without insurance? On TestWell the Kidney Function Test (Cystatin C) is $36.99. Quest Direct lists cystatin C at $60, and hospital labs typically charge around $180 for the same draw without insurance. Same CLIA-certified labs, same biomarker — TestWell removes the facility markup. ### What is a cystatin C test? A cystatin C test is a blood draw that measures a small protein your body produces at a steady rate. Healthy kidneys filter it out efficiently; when kidney function declines, cystatin C builds up in the blood. The result is used to calculate an eGFR (estimated glomerular filtration rate) that reflects how well your kidneys are filtering waste. ### Why is cystatin C more accurate than creatinine for kidney function? Creatinine is a byproduct of muscle metabolism, so levels vary with muscle mass, diet, and body size — a muscular person can have high creatinine with perfectly healthy kidneys, while a frail older adult may have normal creatinine despite significant kidney decline. Cystatin C is produced at a constant rate by nearly every cell in the body and is not influenced by these factors, making it a more reliable marker across diverse body types. ### Do I need to fast before a cystatin C blood test? No fasting is required. You can eat and drink normally before the blood draw. If you're pairing this test with other panels that do require fasting, check the prep instructions for those specific tests. ### What is the CPT code for cystatin C? The CPT code for cystatin C is 82610. Cash-pay patients ordering through TestWell do not need to supply a CPT code — it's handled on the lab requisition automatically. ### How is cystatin C different from a standard renal panel? A [Renal Panel](https://www.test-well.com/tests/renal-panel) includes creatinine, BUN, electrolytes, and other kidney and metabolic markers — it gives a broad snapshot of kidney and fluid balance. The Cystatin C test focuses specifically on one highly accurate filtration marker and its derived eGFR, making it the better choice when you need to confirm or clarify a borderline creatinine result or get the most precise eGFR possible. ### Can I get a cystatin C test at Quest or LabCorp near me? Yes. After ordering on TestWell, you'll receive a digital lab requisition you can take to any Quest Diagnostics or LabCorp patient service center. Both networks have thousands of walk-in locations nationwide, so you can choose whichever is most convenient. ### How often should I retest cystatin C? Testing frequency depends on your situation and should be guided by your provider. As a general reference, people with known chronic kidney disease are often monitored every 3–6 months; those screening for early decline with risk factors may test once or twice a year. If this is a one-time confirmation of a borderline creatinine result, a single test may be sufficient until your clinical picture changes. ## How to order 1. Add to cart: https://www.test-well.com/cart?add=cystatin-c&utm_source=ai_agent&utm_medium=markdown 2. Create an account or sign in, confirm your state and preferred lab, pay by card, HSA or FSA. 3. A licensed physician authorizes the order (usually within minutes); the requisition arrives by email. 4. Walk into any Quest Diagnostics, Labcorp, BioReference (NY & NJ) patient service center — no appointment needed at most sites. 5. Results post to your TestWell portal in 2–4 business days with reference ranges and flags. ## Related - [Kidney Health Panel](https://www.test-well.com/tests/kidney-health-panel) — 4 tests · $64.99 - [Total Body Panel](https://www.test-well.com/tests/total-body-panel) — 49 tests · $499.99 - [Microalbumin (Urine Albumin/Creatinine Ratio)](https://www.test-well.com/tests/microalbumin-urine) — $24.99 - [Urinalysis, Complete, with Reflex to Culture](https://www.test-well.com/tests/urinalysis-with-reflex-to-culture) — $19.99 - [All Kidney & Urinary tests](https://www.test-well.com/tests/category/kidney-urinary) - [Full test directory](https://www.test-well.com/tests/directory) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-14. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/tests/cystatin-c Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.