Free T4 test cost in San Francisco, CA
In San Francisco-Oakland-Fremont, CA, 12 hospitals list a cash price for Free T4 (free thyroxine) thyroid blood test: from $10.80 to $102.48, with a median of $102.48. The lowest listed price is at Stanford Health Care Tri-Valley — $91.68 less than the median here. Across California, the median is $68.12 at 104 hospitals.
Cash prices at 12 facilities across 11 cities for code 84439, as an outpatient — the setting a self-pay patient normally buys. Collected Sep 23, 2026; the hospital files themselves were last updated between Feb 23, 2026 and Jul 22, 2026.
Where each hospital's price falls
Each dot is one hospital's cash price on a scale from the lowest to the highest in San Francisco-Oakland-Fremont, CA.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| Stanford Health Care Tri-Valley lowest Pleasanton, CA HC 6959 Free T4 Equilib Dialysis | $10.80 | $27.00 | — | 60% | Apr 1, 2026 source file |
| Chinese Hospital Association San Francisco, CA Thyroxine (thyroid chemical), free | $46.00 | $46.00 | $4.15–$260.90 | — | Jul 22, 2026 source file |
| Hayward Sisters Hospital Hayward, CA T4FREE | $77.49 | $258.30 | $8.40–$219.56 | 70% | Feb 23, 2026 source file |
| Kaiser Foundation Hospital - Antioch Antioch, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - Redwood City Redwood City, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - San Francisco San Francisco, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - San Leandro San Leandro, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - San Rafael San Rafael, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - South San Francisco South San Francisco, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - Walnut Creek Walnut Creek, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - Oakland/Richmond Oakland, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Kaiser Foundation Hospital - Fremont Fremont, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
| Stanford Health Care Tri-Valley Pleasanton, CA HC Free T4 | $184.00 | $460.00 | — | 60% | Apr 1, 2026 source file |
Outpatient: lowest $10.80, median $102.48, highest $102.48 — a 9.5× difference within the same market.
As an inpatient, the same code is billed by 11 facilities here, median $102.48. Inpatient and outpatient prices are not comparable and are kept on separate pages: the inpatient charge covers admission, not the same purchase.
Cash or insurance?
At 2 of 11 hospitals that publish insurer rates for this code here, the cash price is below the highest rate a health plan has negotiated, and at none is it below every plan's rate. If you have insurance but have not met your deductible, you usually pay your plan's negotiated rate, which falls somewhere in the "Insurers pay" column. Paying cash can cost less, but a cash payment usually does not count toward your deductible. Ask the hospital for both numbers before you book.
What it is
A free T4 test measures thyroxine that is not bound to proteins, the active form of the main thyroid hormone. It is usually ordered with or after a TSH test to check for an underactive or overactive thyroid and to adjust thyroid medicine.
What the price covers
The price usually covers the free T4 test only. The blood draw and the TSH test (84443) are billed separately.