--- title: TSH with Reflex to Free T4 Test type: test id: tsh-reflex-ft4 url: "https://www.test-well.com/tests/tsh-with-reflex-to-free-t4" price_usd: 29.99 lab_fee_usd: 6 all_in_usd: 35.99 category: Thyroid sample: Blood draw fasting_required: false results_in: "1–3 business days" labs: - Quest - Labcorp orderable: true reviewed_at: 2026-10-19 order_url: "https://www.test-well.com/cart?add=tsh-with-reflex-to-free-t4&utm_source=ai_agent&utm_medium=markdown" --- # TSH with Reflex to Free T4 Test > TSH with Reflex to Free T4 measures TSH and Free T4 (reflex) from a standard blood draw. At TestWell it costs $29.99 plus a $6 lab processing fee, needs no fasting, and results post in 1–3 business days. Physician-authorized with no doctor's visit or insurance needed; draw at Quest or Labcorp. ## Key facts | Fact | Value | | --- | --- | | Price | $29.99 + $6 lab processing fee per order ($35.99 all-in for this test alone) | | Sample | Blood draw | | Fasting | Not required | | Results | 1–3 business days | | Labs | Quest Diagnostics, Labcorp | | 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 TSH with Reflex to Free T4 test tell you? The thyroid screen doctors order most: TSH first, and the lab adds free T4 automatically only if TSH comes back abnormal — so one draw gives a diagnosis-ready result when something is off, and costs the same as a plain TSH when nothing is. TSH is the most sensitive single test for thyroid function, but on its own it cannot say how severe an abnormal result is. Free T4 does that — it separates an underactive thyroid (high TSH, low free T4) from the milder subclinical pattern (high TSH, normal free T4), and an overactive thyroid from subclinical hyperthyroidism — but ordering it for everyone adds a test most people do not need. A reflex order solves this: the laboratory runs TSH, and only when the value falls outside its reference range does it run free T4 on the same sample, automatically, with no second visit. This is the screening order most primary-care clinicians write and what the labs call "TSH with reflex to free T4" (Quest 36127, Labcorp 349829). It suits a first thyroid check, routine monitoring where TSH has always been normal, and symptom work-ups where a normal TSH would end the question. If your TSH has been abnormal before, if you take levothyroxine, or if you want the fuller picture regardless, order TSH + Free T4 together or a thyroid panel instead. **Clinical use:** Thyroid testing measures the hormones that regulate metabolism, energy, body temperature, weight, and mood — identifying both overactive and underactive thyroid conditions. ## Who should order it? Anyone with fatigue, weight changes, mood changes, hair loss, cold/heat intolerance, irregular cycles, or family history of thyroid disease. ## Biomarkers measured - [TSH](https://www.test-well.com/biomarkers/tsh) - Free T4 (reflex) ## Price by lab | Lab | Test price | All-in (with $6 fee) | Notes | | --- | --- | --- | --- | | Quest Diagnostics | $29.99 | $35.99 | Choose at checkout; walk-in patient service centers nationwide (not NY/NJ) | | Labcorp | $34.99 | $40.99 | Choose at checkout; walk-in patient service centers nationwide (not NY/NJ) | 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 TSH with Reflex to Free T4 test cost? A TSH with Reflex to Free T4 test costs $29.99 at TestWell — $35.99 all-in, since the $6 lab processing fee is charged once per order and there is no draw or physician fee. Hospital outpatient labs typically bill around $120.00 self-pay. With insurance you pay your plan's negotiated rate against your deductible; TestWell's price is fixed before the draw and HSA/FSA-eligible. | Where you order | Price | One test, all-in | Notes | | --- | --- | --- | --- | | TestWell (drawn at Quest) | $29.99 | $35.99 | Includes the one $6 lab processing fee, charged once per order | | TestWell (drawn at Labcorp) | $34.99 | $40.99 | Labcorp's own cost for this test is higher; same order, same portal, same physician review | | Hospital outpatient lab, self-pay (typical) | $120.00 | $120.00 | Reference figure; hospital charges vary widely by facility and are often higher | ## How do you prepare? No fasting required. Best drawn in the morning when TSH is highest; stop high-dose biotin supplements for two days beforehand, and if you take levothyroxine, take it after the draw. ## Related conditions - [Hypothyroidism](https://www.test-well.com/conditions/thyroid-problems) (E03.9) - [Hyperthyroidism](https://www.test-well.com/conditions/thyroid-problems) (E05.90) ## Common questions about the TSH with Reflex to Free T4 test ### How long do TSH with Reflex to Free T4 results take? Most TSH with Reflex to Free T4 results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment results are ready, with everything viewable in your TestWell portal. ### What sample is collected for the TSH with Reflex to Free T4? Blood draw. A standard venous blood draw, collected at any Quest, Labcorp or BioReference patient service center — walk in with the requisition we email you, no appointment needed at most locations. ### How much does the TSH with Reflex to Free T4 cost without insurance? On TestWell, the TSH with Reflex to Free T4 is $29.99. Walk-in hospital labs typically bill $120 or more without insurance. Insurance is not required — pay one all-in price. ### Do I need to fast before the TSH with Reflex to Free T4? No fasting required for the TSH with Reflex to Free T4. No fasting required. Best drawn in the morning when TSH is highest; stop high-dose biotin supplements for two days beforehand, and if you take levothyroxine, take it after the draw. ### Where can I get the TSH with Reflex to Free T4 done? The TSH with Reflex to Free T4 is available at Quest and Labcorp patient service centers nationwide. Order online at TestWell, pick your preferred lab, and we'll generate a digital requisition for the location closest to you. ### What can throw off a TSH with Reflex to Free T4 test result? Biotin supplements, ashwagandha and thyroid-support supplements and levothyroxine timing can change a TSH with Reflex to Free T4 test result without anything being wrong. Biotin supplements can falsely lower TSH and can falsely raise Free T4 — stop biotin ≥72 hours before the draw. Ashwagandha and thyroid-support supplements can lower TSH and can raise Free T4 — note the supplement on a thyroid panel; a clinician may repeat TSH after a planned pause. Levothyroxine timing can raise Free T4 — draw before the daily dose, then take it. Each is explained on our physician-reviewed "Before your test" pages; when one applies, remove it and retest. ## How to order 1. Add to cart: https://www.test-well.com/cart?add=tsh-with-reflex-to-free-t4&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 patient service center — no appointment needed at most sites. 5. Results post to your TestWell portal in 1–3 business days with reference ranges and flags. ## Related - [Free T3 (Triiodothyronine)](https://www.test-well.com/tests/free-t3) — $30.99 - [Free T4 (Thyroxine)](https://www.test-well.com/tests/free-t4-test) — $23.99 - [Reverse T3](https://www.test-well.com/tests/reverse-t3) — $35.99 - [T3 Uptake](https://www.test-well.com/tests/t3-uptake-test) — $22.99 - [T3, Total (Triiodothyronine)](https://www.test-well.com/tests/total-t3-test) — $24.99 - [All Thyroid tests](https://www.test-well.com/tests/category/thyroid) - [Full test directory](https://www.test-well.com/tests/directory) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-10-19. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/tests/tsh-with-reflex-to-free-t4 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.