Rheumatoid factor test cost in Santa Rosa, CA — inpatient
In Santa Rosa-Petaluma, CA, 3 hospitals list a cash price for rheumatoid factor (RF) test as an inpatient: from $8.67 to $45.36, with a median of $8.67. The lowest listed price is at Providence Santa Rosa Memorial Hospital and 1 other hospital. Across California, the median is $13.20 at 93 hospitals.
Cash prices at 3 facilities across 2 cities for code 86431, 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 |
|---|---|---|---|---|---|
| Providence Santa Rosa Memorial Hospital lowest Santa Rosa, CA · (707) 525-5300 HC RHEUMATOID FACTOR QUANTITATIVE LAB | $8.67 | $17.00 | — | 49% | Apr 1, 2026 source file |
| Petaluma Valley Hospital lowest Petaluma, CA · (707) 778-1111 HC RHEUMATOID FACTOR QUANTITATIVE LAB | $8.67 | $17.00 | — | 49% | Apr 1, 2026 source file |
| Providence Santa Rosa Memorial Hospital Santa Rosa, CA · (707) 525-5300 HC RHEUMATOID FACTOR QUANT | $17.85 | $35.00 | — | 49% | Apr 1, 2026 source file |
| Petaluma Valley Hospital Petaluma, CA · (707) 778-1111 HC RHEUMATOID FACTOR QUANT | $17.85 | $35.00 | — | 49% | Apr 1, 2026 source file |
| Kaiser Foundation Hospital - Santa Rosa Santa Rosa, CA · (707) 571-4000 RHEUMATOID FACTOR QUANTITATIVE | $45.36 | $81.00 | $5.00–$15.00 | 44% | — source file |
Inpatient: lowest $8.67, median $8.67, highest $45.36 — a 5.2× difference within the same market.
As an outpatient, the same code is billed by 3 facilities here, median $8.67 — 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
Rheumatoid factor is an antibody found in many people with rheumatoid arthritis. The test is part of the workup for joint pain and swelling.
What the price covers
The price usually covers running the test. The blood draw (36415) is often billed as a separate line.