CPT
31231 — Nasal endoscopy, diagnostic, unilateral or bilateral
Verify the code matches the actual service and dose.
Cardiology
33533 — CABG using arterial graft, single
This code covers coronary artery bypass grafting (CABG) surgery using a single arterial graft — typically the left internal mammary artery — to bypass a blocked coronary artery and restore blood flow to the heart.
- Typical setting: Hospital, cardiac cath lab
- National avg charge (illustrative): $2,000-$4,000 Medicare allowed for surgeon professional fee (total hospital charges: $70,000-$200,000+; $2,376 average noted by PayerPrice for 2026 fee schedule)
- Most-disputed reason: Incorrect graft count: billing a single-vessel code (33533) when multiple grafts were placed — if two or more arterial grafts were used, add-on code 33534 (two) or 33535 (three) should be appended
What it means
What 33533 actually means
This code covers coronary artery bypass grafting (CABG) surgery using a single arterial graft — typically the left internal mammary artery — to bypass a blocked coronary artery and restore blood flow to the heart. CABG is a major open-heart surgery performed under general anesthesia with cardiopulmonary bypass. This is one of the highest-value surgical codes.
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).
- Incorrect graft count: billing a single-vessel code (33533) when multiple grafts were placed — if two or more arterial grafts were used, add-on code 33534 (two) or 33535 (three) should be appended
- Mixed graft type confusion: billing 33533 (arterial) when a saphenous vein graft was used — venous CABG grafts use a different code family (33510-33516)
- Unbundling cardiopulmonary bypass: separately billing for CPB that is already included in the CABG global surgical package
If you see 33533 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 33533 often also see these adjacent codes on the same bill.
CPT
31237 — Nasal/sinus endoscopy, surgical; with biopsy, polypectomy, or debridement
Verify the code matches the actual service and dose.
CPT
36415 — Routine venipuncture for collection of specimen
Verify the code matches the actual service and dose.
CPT
36416 — Collection of capillary blood specimen, finger, heel, or ear stick
Verify the code matches the actual service and dose.
CPT
38221 — Bone marrow biopsy, needle; first sampling
Verify the code matches the actual service and dose.
Related BillBusted guides
Plain-English reads if you see 33533 on a bill.
33533 FAQ
Plain-English answers.
What does 33533 usually cost?
$2,000-$4,000 Medicare allowed for surgeon professional fee (total hospital charges: $70,000-$200,000+; $2,376 average noted by PayerPrice for 2026 fee schedule). 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 33533?
Incorrect graft count: billing a single-vessel code (33533) when multiple grafts were placed — if two or more arterial grafts were used, add-on code 33534 (two) or 33535 (three) should be appended
What should I do if I see 33533 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 33533 before paying.
Don't pay 33533 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.