Phosphorus test cost in Seattle, WA
In Seattle-Tacoma-Bellevue, WA, 18 hospitals list a cash price for phosphorus (phosphate) blood test: from $19.60 to $56.80, with a median of $29.31. The lowest listed price is at Valley Medical Center — $9.71 less than the median here. Across Washington, the median is $40.00 at 59 hospitals.
Cash prices at 18 facilities across 14 cities for code 84100, as an outpatient — the setting a self-pay patient normally buys. Collected Sep 27, 2026; the hospital files themselves were last updated between Feb 28, 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 Seattle-Tacoma-Bellevue, WA.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| Valley Medical Center lowest Renton, WA · (425) 228-3450 Assay of Phosphorus Inorganic | $19.60 | $28.00 | — | 30% | — source file |
| Saint Clare Hospital Lakewood, WA · (253) 588-1711 HC PHOSPHORUS | $21.14 | $73.33 | $4.74–$55.00 | 71% | Feb 28, 2026 source file |
| St Anthony Hospital Gig Harbor, WA · (253) 530-2050 HC PHOSPHORUS | $22.31 | $73.33 | $4.74–$55.00 | 70% | Feb 28, 2026 source file |
| Highline Medical Center Burien, WA · (206) 431-5237 HC PHOSPHORUS | $22.40 | $73.33 | $4.74–$66.00 | 69% | Feb 28, 2026 source file |
| St Francis Community Hospital Federal Way, WA · (253) 944-8100 HC PHOSPHORUS | $23.02 | $73.33 | $4.74–$55.00 | 69% | Feb 28, 2026 source file |
| Virginia Mason Medical Center Seattle, WA · (206) 223-6600 PHOSPHORUS | $23.97 | $47.00 | $28.20–$37.60 | 49% | — source file |
| Snoqualmie Valley Hospital Snoqualmie, WA · (425) 831-2300 Facility Fee HC ASSAY OF INORGANIC PHOSPHORUS | $24.28 | $41.86 | $4.65–$38.51 | 42% | — source file |
| Snoqualmie Valley Hospital Snoqualmie, WA · (425) 831-2300 Facility Fee HC PHOSPHORUS-LC | $24.28 | $41.86 | $4.65–$38.51 | 42% | — source file |
| St Joseph Medical Center Tacoma, WA · (253) 627-4101 HC PHOSPHORUS | $24.29 | $73.33 | $4.74–$55.00 | 67% | Feb 28, 2026 source file |
| St Elizabeth Hospital Enumclaw, WA · (360) 825-2505 HC PHOSPHORUS | $25.92 | $73.33 | $4.74–$66.00 | 65% | Feb 28, 2026 source file |
| Seattle Children's Hospital Seattle, WA · (206) 987-2000 Esrd Assay of Phosphorus | $32.70 | $32.70 | $8.24–$31.39 | — | — source file |
| Overlake Medical Center & Clinics Bellevue, WA · (425) 688-5000 Hc Assay Of Inorganic Phosphorus | $34.50 | $69.00 | — | 50% | Apr 1, 2026 source file |
| Swedish Edmonds Edmonds, WA · (425) 640-4000 HC ASSAY PHOSPHORUS | $35.04 | $73.00 | — | 52% | Apr 1, 2026 source file |
| Swedish Medical Center / Cherry Hill Seattle, WA · (206) 320-2000 HC ASSAY PHOSPHORUS | $35.04 | $73.00 | — | 52% | Apr 1, 2026 source file |
| Swedish Issaquah Issaquah, WA · (425) 313-4000 HC ASSAY PHOSPHORUS | $35.04 | $73.00 | — | 52% | Apr 1, 2026 source file |
| Swedish Medical Center Seattle, WA · (206) 386-6000 HC ASSAY PHOSPHORUS | $35.04 | $73.00 | — | 52% | Apr 1, 2026 source file |
| Providence Regional Medical Center Everett Everett, WA · (425) 261-2000 HC ASSAY PHOSPHORUS | $37.96 | $73.00 | — | 48% | Apr 1, 2026 source file |
| Cascade Valley Hospital Arlington, WA · (360) 435-2133 HC ASSAY OF PHOSPHORUS | $49.60 | $62.00 | $4.74–$55.80 | 20% | — source file |
| Kaiser Permanente Central Hospital Seattle, WA · (206) 326-3000 PHOSPHORUS INORGANIC (PHOSPHATE) | $56.80 | $71.00 | $4.00–$15.00 | 20% | Apr 1, 2026 source file |
| Seattle Children's Hospital Seattle, WA · (206) 987-2000 Phosphorus, Body Fluid | $67.00 | $67.00 | $16.88–$64.32 | — | — source file |
| Seattle Children's Hospital Seattle, WA · (206) 987-2000 Phosphorus, Serum | $67.00 | $67.00 | $16.88–$64.32 | — | — source file |
Outpatient: lowest $19.60, median $29.31, highest $56.80 — a 2.9× difference within the same market.
As an inpatient, the same code is billed by 19 facilities here, median $25.92. 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 9 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 1 it is 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.