C-peptide test cost in St. Louis, MO — inpatient
In St. Louis, MO-IL, 7 hospitals list a cash price for C-peptide blood test as an inpatient: from $63.00 to $539.06, with a median of $130.32. The lowest listed price is at Carlinville Area Hospital — $67.32 less than the median here. Across Missouri, the median is $105.75 at 61 hospitals.
Cash prices at 7 facilities across 7 cities for code 84681, as an inpatient (admitted to hospital) . Collected Sep 27, 2026; the hospital files themselves were last updated between Feb 6, 2026 and Mar 16, 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 |
|---|---|---|---|---|
| Carlinville Area Hospital lowest Carlinville, IL · (217) 854-3141 C-PEPTID source file | $63.00 | $90.00 | $55.98–$3,396.04 | 30% |
| Mercy Rehabilitation Hospital South Louis, MO C-PEPTIDE File of Mar 16, 2026 · source file | $72.10 | $72.10 | $72.10 | — |
| Community Hospital of Staunton Staunton, IL · (618) 635-2200 C PEPTIDE File of Feb 9, 2026 · source file | $103.45 | $206.90 | $175.86–$188.28 | 50% |
| Hshs Holy Family Hospital Greenville, IL · (618) 664-1230 HC C PEPTIDE-90 source file | $130.32 | $181.00 | $8.82–$181.00 | 28% |
| Anderson Hospital Maryville, IL · (618) 288-5711 C PEPTIDE File of Feb 6, 2026 · source file | $133.40 | $266.80 | $200.10–$240.12 | 50% |
| Carlinville Area Hospital Carlinville, IL · (217) 854-3141 C-PEPTIDE 24 HR URINE(REF) source file | $136.50 | $195.00 | $121.29–$3,396.04 | 30% |
| Carlinville Area Hospital Carlinville, IL · (217) 854-3141 C-PEPTIDE(REF) source file | $188.30 | $269.00 | $167.32–$3,396.04 | 30% |
| Mercy Rehabilitation Hospital St. Louis Chesterfield, MO C-PEPTIDE File of Mar 16, 2026 · source file | $249.85 | $249.85 | $249.85 | — |
| Gateway Regional Medical Center Granite City, IL · (618) 798-3000 Q372 C-PEPTIDE IA+1 more line at this price source file | $539.06 | $898.44 | $898.44 | 40% |
Inpatient: lowest $63.00, median $130.32, highest $539.06 — a 8.6× difference within the same market.
As an outpatient, the same code is billed by 12 facilities here, median $109.71 — that is the price to compare if you are not being admitted.
Cash or insurance?
At 5 of 7 hospitals that publish insurer rates for this code here, the cash price is below the highest rate a health plan has negotiated, and at 3 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 C-peptide test shows how much insulin the pancreas is making. It helps tell type 1 from type 2 diabetes and find the cause of low blood sugar.
What the price covers
The price usually covers running the test. The blood draw (36415) is often billed as a separate line.