Free T4 test cost in Napa, CA — inpatient
In Napa, CA, 1 hospital lists a cash price for Free T4 (free thyroxine) thyroid blood test as an inpatient: from $55.85 to $55.85, with a median of $55.85. Across California, the median is $68.12 at 104 hospitals.
Cash prices at 1 facility 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.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| St Joseph Health Northern California LLC Napa, CA HC ASSAY OF FREE THYROXINE CDM | $55.85 | $109.50 | — | 49% | Apr 1, 2026 source file |
Inpatient: lowest $55.85, median $55.85, highest $55.85.
As an outpatient, the same code is billed by 1 facility here, median $55.85 — that is the price to compare if you are not being admitted.
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.
1 row held back from this comparison
It is 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 Napa, CAHC ASSAY OF FREE THYROXINE LAB | $5.10 | file |