Potassium test cost in St. Louis, MO
In St. Louis, MO-IL, 17 hospitals list a cash price for potassium blood test: from $5.28 to $79.20, with a median of $44.85. The lowest listed price is at Ranken Jordan Pediatric Bridge Hospital — $39.57 less than the median here. Across Missouri, the median is $41.32 at 64 hospitals.
Cash prices at 17 facilities across 15 cities for code 84132, as an outpatient — the setting a self-pay patient normally buys. Collected Sep 27, 2026; the hospital files themselves were last updated between Feb 6, 2026 and Apr 24, 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 St. Louis, MO-IL.
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list | File date |
|---|---|---|---|---|---|
| Ranken Jordan Pediatric Bridge Hospital lowest Maryland Heights, MO · (314) 872-6400 Potassium Level | $5.28 | $6.60 | — | 20% | Apr 24, 2026 source file |
| Mercy Hospital Jefferson Festus, MO · (636) 933-1000 Potassium Plasma/Wb | $16.25 | $25.00 | $4.28–$10.71 | 35% | — source file |
| St Elizabeths Hospital of the Hospital Sisters of the Third Order of St Francis O'Fallon, IL · (618) 234-2120 HC POTASSIUM | $25.92 | $36.00 | $3.80–$36.00 | 28% | — source file |
| Mercy Hospital Washington Washington, MO · (636) 239-8000 POC Potassium Ser Plasma Wb | $27.30 | $42.00 | $4.28–$7.78 | 35% | — source file |
| Gateway Regional Medical Center Granite City, IL · (618) 798-3000 POTASSIUM SER PL WB | $28.29 | $47.15 | $47.15 | 40% | — source file |
| Mercy Hospital South Saint Louis, MO · (314) 525-1000 Potassium Plasma/Wb | $33.80 | $52.00 | $4.28–$10.71 | 35% | — source file |
| Mercy Hospital Washington Washington, MO · (636) 239-8000 Potassium Plasma/Wb | $34.45 | $53.00 | $4.28–$7.78 | 35% | — source file |
| Mercy Hospital South Saint Louis, MO · (314) 525-1000 POC Potassium Ser Plasma Wb | $35.10 | $54.00 | $4.28–$10.71 | 35% | — source file |
| Shriners Childrens - St Louis Saint Louis, MO · (314) 432-3600 ASSAY OF SERUM POTASSIUM | $36.10 | $36.10 | $2.59–$7.90 | — | — source file |
| Touchette Regional Hospital Cahokia Heights, IL · (618) 332-3060 Potassium; serum, plasma or whole blood | $38.44 | $62.00 | $2.36–$59.00 | 38% | — source file |
| Mercy Hospital Lincoln Troy, MO · (636) 528-8551 POC Potassium Ser Plasma Wb | $44.85 | $69.00 | $4.76–$6.59 | 35% | — source file |
| Mercy Hospital Lincoln Troy, MO · (636) 528-8551 Potassium Plasma/Wb | $44.85 | $69.00 | $4.76–$6.59 | 35% | — source file |
| Mercy Hospital Jefferson Festus, MO · (636) 933-1000 POC Potassium Ser Plasma Wb | $44.85 | $69.00 | $4.49–$69.00 | 35% | — source file |
| Mercy Hospital St Louis Saint Louis, MO · (314) 251-6000 POC Potassium Ser Plasma Wb | $48.75 | $75.00 | $4.88–$75.00 | 35% | — source file |
| Mercy Hospital St Louis Saint Louis, MO · (314) 251-6000 Potassium Plasma/Wb | $48.75 | $75.00 | $4.88–$75.00 | 35% | — source file |
| Anderson Hospital Maryville, IL · (618) 288-5711 POTASSIUM LEVEL | $49.90 | $99.80 | $4.45–$89.82 | 50% | Feb 6, 2026 source file |
| Community Hospital of Staunton Staunton, IL · (618) 635-2200 POTASSIUM LEVEL | $55.70 | $111.40 | $32.21–$101.37 | 50% | Feb 9, 2026 source file |
| Hshs Holy Family Hospital Greenville, IL · (618) 664-1230 HC POTASSIUM | $62.64 | $87.00 | $3.99–$87.00 | 28% | — source file |
| Jersey Community Hospital Jerseyville, IL · (618) 498-6402 Potassium Level | $63.00 | $63.00 | $32.95–$53.55 | — | — source file |
| St Josephs Hospital Hospital Sisters Third Order of St Francis Breese, IL · (618) 526-4511 HC POTASSIUM | $72.00 | $100.00 | $3.80–$100.00 | 28% | — source file |
| Carlinville Area Hospital Carlinville, IL · (217) 854-3141 POTASSIUM | $72.10 | $103.00 | $37.08–$147.14 | 30% | — source file |
| St Josephs Hospital of the Hospital Sisters of the Third Order of St Francis Highland, IL · (618) 651-2600 HC POTASSIUM | $79.20 | $110.00 | $8.84–$110.00 | 28% | — source file |
Outpatient: lowest $5.28, median $44.85, highest $79.20 — a 15.0× difference within the same market.
As an inpatient, the same code is billed by 13 facilities here, median $58.35. 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 10 of 16 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 potassium test measures the level of potassium in the blood. Doctors check it for people on diuretics or blood pressure drugs, with kidney disease, an irregular heartbeat, or vomiting and diarrhea.
What the price covers
The price usually covers running the test. The blood draw (36415) is often billed as a separate line.