Magnesium test cost in Napa, CA
In Napa, CA, 1 hospital lists a cash price for Magnesium blood test: from $17.85 to $17.85, with a median of $17.85. Across California, the median is $106.08 at 103 hospitals.
Cash prices at 1 facility for code 83735, as an outpatient — the setting a self-pay patient normally buys. 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 Napa, CA.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| St Joseph Health Northern California LLC lowest Napa, CA HC MAGNESIUM QUANT URINE | $17.85 | $35.00 | — | 49% | Apr 1, 2026 source file |
| St Joseph Health Northern California LLC Napa, CA HC ASSAY OF MAGNESIUM LAB | $34.55 | $67.75 | — | 49% | Apr 1, 2026 source file |
| St Joseph Health Northern California LLC Napa, CA HC MAGNESIUM QUANT URINE | $60.18 | $118.00 | — | 49% | Apr 1, 2026 source file |
| St Joseph Health Northern California LLC Napa, CA HC ASSAY OF MAGNESIUM CDM | $60.18 | $118.00 | — | 49% | Apr 1, 2026 source file |
Outpatient: lowest $17.85, median $17.85, highest $17.85.
As an inpatient, the same code is billed by 1 facility here, median $17.85. Inpatient and outpatient prices are not comparable and are kept on separate pages: the inpatient charge covers admission, not the same purchase.
What it is
A magnesium test measures the level of magnesium in the blood. Doctors order it for muscle cramps or weakness, an irregular heartbeat, low potassium or calcium that does not correct, and for people on diuretics, long-term acid-reducing drugs or with kidney disease.
What the price covers
The price usually covers running the test. The blood draw (36415) is often billed as a separate line.
1 row held back from this comparison
It is priced below $1 or below a tenth of the national median for code 83735 ($43.50). 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 MAGNESIUM CDM | $4.30 | file |