Lab & pathology
85610 — Prothrombin time
A blood clotting test that measures how long it takes blood plasma to clot, used to monitor patients on warfarin (Coumadin) or to evaluate bleeding disorders before surgery.
- Typical setting: Hospital lab, reference lab, doctor's office
- National avg charge (illustrative): $5–$15 Medicare allowed (CMS CLFS); $10–$45 commercial; varies by region
- Most-disputed reason: Confusing 85610 (PT) with 85730 (PTT/aPTT) — both are clotting tests but measure different pathways and are separately billable when both are ordered
What it means
What 85610 actually means
A blood clotting test that measures how long it takes blood plasma to clot, used to monitor patients on warfarin (Coumadin) or to evaluate bleeding disorders before surgery. Results are often reported as an INR (International Normalized Ratio) to standardize results across labs.
Common errors with this code
What goes wrong on real bills.
Most bills that look correct still contain at least one of these issues. Up to 49% of medical bills contain errors (CFPB).
- Confusing 85610 (PT) with 85730 (PTT/aPTT) — both are clotting tests but measure different pathways and are separately billable when both are ordered
- Billing 85610 and 85611 (PT, substitution) together without distinct documentation
- Duplicate billing when both an ordering provider office and an outpatient lab bill for the same PT result
If you see 85610 on your bill
Three steps before paying.
1. Get the itemized bill. If your statement only shows a summary, request the CPT-level itemized bill before paying. Generate the request language →
2. Cross-check against the EOB. Compare what your insurer's Explanation of Benefits says you owe versus what the hospital is asking. They disagree more often than people think. Read the bill-vs-EOB guide →
3. Run a free Bill Scan. Upload the bill (and EOB if you have it) and BillBusted will flag the most likely issues with this specific code in your specific state. Run free scan →
Related codes
Other codes in this category.
People who land on 85610 often also see these adjacent codes on the same bill.
CPT
80050 — General health panel; includes CBC w/diff, CMP, TSH
Lab — check for unbundling and duplicate billing.
CPT
80051 — Electrolyte panel; CO2, chloride, potassium, sodium
Lab — check for unbundling and duplicate billing.
CPT
80053 — Comprehensive metabolic panel
If individual blood tests are also on your bill, you may have an unbundling error.
CPT
80055 — Obstetric panel; CBC w/diff, HBsAg, rubella Ab, syphilis, RBC Ab screen, ABO/Rh
Lab — check for unbundling and duplicate billing.
CPT
80061 — Lipid panel (cholesterol)
If you see HDL or LDL listed separately next to 80061, that's unbundling.
Related BillBusted guides
Plain-English reads if you see 85610 on a bill.
85610 FAQ
Plain-English answers.
What does 85610 usually cost?
$5–$15 Medicare allowed (CMS CLFS); $10–$45 commercial; varies by region. Costs vary by region, payer contract, and whether the service was performed in a hospital outpatient department (which adds a facility fee) versus a free-standing clinic.
What's the most common billing error on 85610?
Confusing 85610 (PT) with 85730 (PTT/aPTT) — both are clotting tests but measure different pathways and are separately billable when both are ordered
What should I do if I see 85610 on my bill?
Request the itemized bill and the matching EOB from your insurer. Compare the units/quantity billed against what you actually received. Run a free BillBusted scan to flag the most likely errors specific to 85610 before paying.
Don't pay 85610 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.