CPT code 01920: Anesthesia for cardiac catheterization

Key Takeaways

CPT code 01920 covers anesthesia for a diagnostic cardiac catheterization, including coronary angiography and ventriculography. The descriptor specifically excludes Swan-Ganz catheter placement.

The code carries 7 base units. Total payment works out to (Base Units + Time Units + Qualifying Circumstance Units) x Conversion Factor, with time billed in 15-minute units under Medicare.

Physical status modifiers P1-P6 belong on every claim, but Medicare pays zero extra units for them. Some commercial payers still add units, so check the contract before assuming otherwise.

Claims management software can check the insurer-submission fields on an anesthesia claim and gate it from going out until they’re complete, but it won’t calculate anesthesia units or choose modifiers for you.

A cardiac catheterization case looks simple on paper: one patient, one code, one anesthesia team. Then the claim bounces back because someone billed 01925 instead of 01920, or assumed a P3 modifier would add extra units.

CPT code 01920 covers anesthesia for a diagnostic cardiac catheterization, including coronary angiography and ventriculography. Getting the code right is the easy part. The base units, the time formula, and the modifiers around it are what actually decide whether the claim pays the first time.

What CPT code 01920 actually covers

The American Medical Association‘s official descriptor for CPT code 01920 reads: Anesthesia for cardiac catheterization including coronary angiography and ventriculography (not to include Swan-Ganz catheter).

That last clause matters. If the anesthesia team also manages a Swan-Ganz (pulmonary artery) catheter during the same case, that work sits outside 01920’s scope. Don’t assume the code’s 7 base units already account for it. Check whether it needs separate documentation and, where applicable, separate billing.

01920 is a diagnostic code by design. It covers the anesthesia for visualizing the coronary arteries and heart chambers. That’s true whether or not a therapeutic intervention follows in the same session. Both physician anesthesiologists and CRNAs bill it, and the provider-type modifier decides how the payment splits between them.

Per CMS’s National Correct Coding Initiative policy manual, 01920 can also be reported for monitored anesthesia care (MAC), not just general anesthesia. That applies to patients who are critically ill or unstable. Medical necessity for that call still falls under national CMS policy and local contractor coverage rules.

CPT 01920’s base units and where it sits in the radiology-anesthesia family

CPT code 01920 carries 7 base units. That’s the fixed value the AMA assigns to reflect the complexity and risk of the anesthesia service. The number doesn’t change no matter how long the case runs.

The code sits in CPT’s anesthesia-for-radiological-procedures section. 01916, 01920, and 01922 cover diagnostic and non-invasive work, while 01924 through the 01930s cover therapeutic interventional radiology instead. That’s a distinction worth knowing. 01920 and 01925 both touch the coronary arteries and get mixed up often.

The dividing line is diagnostic versus therapeutic, not anatomy. A catheterization done purely to visualize the coronary arteries is 01920. The moment the physician crosses into a therapeutic intervention, the anesthesia code moves to 01925 instead. Think angioplasty or stenting on the coronary or carotid arteries.

More specific venous and lymphatic codes (01931-01933) exist further along the same family. They cover sites like the portal circulation, the jugular vein, and intracranial venous access. Confirm the exact base unit value for those against the current-year CMS Physician Fee Schedule, since sources vary slightly year to year.

Always verify the current base unit value against the CMS schedule or the AAPC CPT code reference before billing. Base units don’t change often, but confirming against the current year’s data is still best practice.

How the anesthesia billing formula works for CPT 01920

Anesthesia billing doesn’t run on the RVU-based fee schedule that prices most CPT codes. Instead, the formula is:

(Base Units + Time Units + Qualifying Circumstance Units) x Conversion Factor = Allowed Amount

Time gets converted into units, typically one unit per 15 minutes under Medicare. That count runs from when the provider starts preparing the patient through transfer of care to recovery. The 15-minute rule doesn’t change based on which anesthesia code is billed, whether that’s 01920, 01840, or 01730.

Some commercial payers and state Medicaid programs use a different divisor, so confirm the rule before assuming Medicare’s applies.

A worked example

Take a 90-minute cardiac catheterization billed under 01920 with modifier AA. That’s 6 time units (90 minutes / 15). Add the 7 base units, and there are 13 total units before any qualifying circumstance add-ons.

Medicare finalizes a slightly higher conversion factor for clinicians in qualifying alternative payment models. Every rate then gets adjusted further for locality. Treat the figure above as an illustration of the mechanics, not a quote for any specific claim.

Modifiers that apply to CPT code 01920

Provider-type and payment modifiers

These modifiers tell the payer who delivered the anesthesia and under what supervision arrangement. That’s what actually sets the payment rate.

Where a state has opted out of the Medicare physician supervision requirement, a CRNA can bill 01920 independently under QZ. If supervision is required instead, the claim splits between the anesthesiologist (QK) and the CRNA (QX), each getting half the allowed amount.

Physical status modifiers (P1-P6)

The American Society of Anesthesiologists defines six physical status levels, and one belongs on every anesthesia claim, including 01920.

Medicare treats P1-P6 as informational only. It pays zero additional units for any of them, even P4 on a genuinely high-risk cath patient. A handful of commercial payers still add units for the higher classifications. Check each payer’s contract instead of assuming Medicare’s rule applies across the board.

Medicare reimbursement for CPT 01920: How the payment actually gets calculated

Medicare’s math for CPT code 01920 is the standard anesthesia formula. It just runs through whichever conversion factor applies to the billing clinician and locality.

CMS finalized the national anesthesia conversion factor for 2026 at $20.4976 for most physicians, a small increase over 2025. Clinicians in qualifying alternative payment models get a marginally higher rate. Locality adjustments move the number further, so pull the current figure from the CMS Physician Fee Schedule tool rather than reusing last year’s rate.

Two things trip people up on the Medicare side specifically. First, physical status modifiers never add units, no matter how sick the patient is. Second, the qualifying circumstance add-on codes carry a Status B “bundled” indicator on the Medicare Physician Fee Schedule. That group includes 99100 (extreme age), 99116 (total body hypothermia), 99135 (controlled hypotension), and 99140 (emergency conditions). Report them when they genuinely apply, but don’t expect a separate line-item payment.

Commercial payers are trending the same direction. UnitedHealthcare, for one, eliminated separate payment for those same qualifying circumstance codes and for P3-P5 modifiers on its commercial and individual exchange plans, effective October 1, 2025. Ohio followed a month later, on November 1. Its Medicare Advantage plans already followed CMS’s non-payment approach beforehand. Confirm the current policy for each payer before building a reimbursement estimate around them.

Common denial reasons for CPT 01920 claims

Based on standard anesthesia billing patterns, these are the most frequent denial drivers for CPT code 01920:

• Wrong code selection: the operative report documents a therapeutic intervention (angioplasty, stenting) on the coronary or carotid arteries. 01920 was billed instead of 01925.
• Time unit mismatch: the billed time units don’t match the start and stop timestamps on the anesthesia record.
• Missing or unsupported physical status modifier: no P-modifier on the claim, or a P3-or-higher modifier with nothing in the pre-anesthesia note to justify it.
• Provider modifier error: a CRNA modifier submitted without supervision documentation on file, or an AA/QK mismatch between the anesthesiologist’s and CRNA’s claims.
• Swapped qualifying circumstance codes: 99116 (hypothermia) and 99135 (hypotension) get transposed often. Give both a second look before either goes on a claim.
• Diagnosis mismatch: the ICD-10 code on file doesn’t support a diagnostic catheterization.

Before you submit

Run through this before a 01920 claim goes out the door. The same checklist habit works just as well for a 01430 claim, or an 01842 claim.

• Confirm the operative note describes a diagnostic catheterization, not a therapeutic intervention.
• Confirm anesthesia start and stop times are logged and match the billed time units.
• Confirm a physical status modifier is on the claim and supported by the pre-anesthesia evaluation.
• Confirm the provider-type modifier matches how the case was actually staffed that day.
• Confirm whether a Swan-Ganz catheter was placed, and document or bill it separately if so.
• Confirm the ICD-10 code supports a diagnostic cardiac catheterization.

Where Pabau fits in the anesthesia billing workflow

Anesthesia billing for CPT code 01920 depends on documentation moving cleanly between the cardiologist’s cath lab, the anesthesia team, and the biller. The same handoff problem shows up in outpatient specialties too, like plastic surgery and OB/GYN practices running their own anesthesia days.

Practice management software like Pabau keeps pre-anesthesia evaluations, consent forms, and clinical notes attached to one patient record. That way, the physical status justification and the anesthesia timing sit exactly where the biller needs them.

Pabau’s claims management feature checks the required insurer-submission fields, like membership and authorization numbers, before a claim goes out. The claim stays gated until those fields are complete, and the billing team gets one dashboard to track status from there.

What it doesn’t do is calculate anesthesia base or time units, or choose between AA and QK for you. That’s still a coding decision for the anesthesia biller. The tool’s job is keeping the administrative side of the claim clean. That way, a 01920 claim isn’t denied over a missing field that had nothing to do with the anesthesia itself.

Conclusion

Billing CPT code 01920 cleanly comes down to three habits. Confirm the case was diagnostic, not a therapeutic intervention. Document time and physical status well enough to survive a payer audit. Apply the right provider-type modifier for how the case was staffed.

Get those three right, and the base units and conversion factor take care of themselves. To see how Pabau keeps that documentation and claims workflow in one place, book a demo.

Continue your research

Billing the therapeutic version of this case instead? 01925 covers anesthesia for a coronary or carotid interventional radiology procedure, not a diagnostic cath.

Treating a patient over 70 or under one year old? 99100 is the qualifying circumstances add-on code for extreme age, and it explains why Medicare still won’t pay for it separately.

Want the full picture on anesthesia modifiers? Claims management software shows how the submission checks work before a claim goes out.

Comparing base units across the radiology-anesthesia family? 01924 covers therapeutic arterial interventional radiology, one step over from a straightforward diagnostic cath.

Frequently asked questions