Phosphorus test cost in San Francisco, CA
In San Francisco-Oakland-Fremont, CA, 25 hospitals list a cash price for phosphorus (phosphate) blood test: from $35.91 to $152.00, with a median of $79.20. The lowest listed price is at St. Rose Hospital — $43.29 less than the median here. Across California, the median is $75.60 at 198 hospitals.
Cash prices at 25 facilities across 17 cities for code 84100, as an outpatient — the setting a self-pay patient normally buys. Collected Sep 29, 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 |
|---|---|---|---|---|
| St. Rose Hospital lowest Hayward, CA · (510) 782-6200 PHOSPHORUS File of Feb 23, 2026 · source file | $35.91 | $119.70 | $4.41–$101.75 | 70% |
| Sequoia Hospital Redwood City, CA · (650) 369-5811 PHOSPHORUS File of Feb 28, 2026 · source file | $61.52 | $169.00 | $4.74–$138.58 | 64% |
| Kaiser Foundation Hospital - Antioch Antioch, CA · (925) 813-6500 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - San Leandro San Leandro, CA · (510) 454-1000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - Fremont Fremont, CA · (510) 784-4000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - San Francisco San Francisco, CA · (415) 833-2646 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - South San Francisco South San Francisco, CA · (650) 742-3200 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - Oakland/Richmond Oakland, CA · (510) 752-1000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Fnd Hospital - Richmond Campus Richmond, CA · (510) 752-1000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - Redwood City Redwood City, CA · (650) 299-2000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - San Rafael San Rafael, CA · (415) 444-2000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Kaiser Foundation Hospital - Walnut Creek Walnut Creek, CA · (925) 295-4000 ASSAY OF PHOSPHORUS INORGANIC source file | $75.60 | $135.00 | $5.00–$15.00 | 44% |
| Stanford Health Care Tri-Valley Pleasanton, CA · (925) 847-3000 HC Phosphorus Serum/ File of Apr 1, 2026 · source file | $79.20 | $198.00 | — | 60% |
| Alta Bates Summit Medical Center - Herrick Campus Berkeley, CA · (510) 204-4444 HCHG PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Mills-Peninsula Medical Center Burlingame, CA · (650) 696-5400 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Sutter Delta Medical Center Antioch, CA · (925) 779-7200 HCHG PHOSPHORUS (PO4) File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Alta Bates Summit Medical Center-Summit Campus-Hawthorne Oakland, CA · (510) 655-4000 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Novato Community Hospital Novato, CA · (415) 209-1300 HCHG PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Mills Health Center San Mateo, CA · (650) 696-5400 HCHG PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Alta Bates Summit Medical Center Oakland, CA · (510) 655-4000 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| California Pacific Medical Ctr-Davies Campus Hospital San Francisco, CA · (415) 600-6000 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Eden Medical Center Castro Valley, CA · (510) 537-1234 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Alta Bates Summit Medical Center - Alta Bates Camp Berkeley, CA · (510) 204-4444 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| California Pacific Medical Center- Van Ness Campus San Francisco, CA · (415) 600-6000 HCHG CORE PHOSPHORUS (PO4)+1 more line at this price File of Apr 1, 2026 · source file | $142.00 | $142.00 | — | — |
| Chinese Hospital San Francisco, CA · (415) 677-2480 Phosphate level File of Jul 22, 2026 · source file | $152.00 | $152.00 | $4.74–$273.60 | — |
Outpatient: lowest $35.91, median $79.20, highest $152.00 — a 4.2× difference within the same market.
As an inpatient, the same code is billed by 24 facilities here, median $142.00. 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 3 of 13 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 phosphorus test measures phosphate in the blood. It is used with calcium for kidney disease, bone disease and parathyroid problems.
What the price covers
The price usually covers running the test. The blood draw (36415) is often billed as a separate line.