Free T4 test cost in Santa Rosa, CA — inpatient
In Santa Rosa-Petaluma, CA, 4 hospitals list a cash price for Free T4 (free thyroxine) thyroid blood test as an inpatient: from $55.85 to $102.48, with a median of $56.23. The lowest listed price is at St Joseph Health Northern California LLC and 1 other hospital — $0.38 less than the median here. Across California, the median is $68.12 at 104 hospitals.
Cash prices at 4 facilities across 3 cities for code 84439, as an inpatient (admitted to hospital) . Collected Sep 23, 2026; the hospital files themselves were last updated between Apr 1, 2026 and Apr 1, 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 Santa Rosa-Petaluma, CA.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| St Joseph Health Northern California LLC lowest Santa Rosa, CA HC ASSAY OF FREE THYROXINE CDM | $55.85 | $109.50 | — | 49% | Apr 1, 2026 source file |
| NorCal HealthConnect LLC lowest Petaluma, CA HC ASSAY OF FREE THYROXINE CDM | $55.85 | $109.50 | — | 49% | Apr 1, 2026 source file |
| NorCal HealthConnect LLC Healdsburg, CA HC ASSAY OF FREE THYROXINE CDM | $56.61 | $111.00 | — | 49% | Apr 1, 2026 source file |
| NorCal HealthConnect LLC Healdsburg, CA HC ASSAY OF FREE THYROXINE LAB | $66.30 | $130.00 | — | 49% | Apr 1, 2026 source file |
| Kaiser Foundation Hospital - Santa Rosa Santa Rosa, CA ASSAY OF FREE THYROXINE | $102.48 | $183.00 | $8.00–$25.00 | 44% | — source file |
Inpatient: lowest $55.85, median $56.23, highest $102.48 — a 1.8× difference within the same market.
As an outpatient, the same code is billed by 4 facilities here, median $56.23 — that is the price to compare if you are not being admitted.
Cash or insurance?
At the one hospital here that publishes insurer rates for this code, the cash price is not below the highest rate a health plan has negotiated. 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.
2 rows held back from this comparison
They are priced below $1 or below a tenth of the national median for code 84439 ($60.00). Such a line is almost always a physician's fee billed separately, an assistant's share or a placeholder — a real charge, but not the price of the procedure itself.
| St Joseph Health Northern California LLC Santa Rosa, CAHC ASSAY OF FREE THYROXINE LAB | $5.10 | file |
| NorCal HealthConnect LLC Petaluma, CAHC ASSAY OF FREE THYROXINE LAB | $5.10 | file |