CPT code 01150: Anesthesia for pelvic tumor surgery billing guide

Key Takeaways

CPT code 01150 describes anesthesia for radical procedures for tumor of pelvis, except hindquarter amputation, maintained by the American Medical Association (AMA).

The code carries 10 base units per VA Community Care and DOL OWCP fee schedules; total anesthesia units equal base units plus time units.

Applicable anesthesia modifiers include AA, QK, QX, QZ, and QY depending on the provider type and supervision model; selecting the wrong modifier is a leading denial trigger.

Pabau’s claims management software supports accurate anesthesia billing workflows, reducing claim errors and improving reimbursement turnaround for surgical practices.

CPT code 01150 is defined by the American Academy of Professional Coders (AAPC) as anesthesia for radical procedures for tumor of pelvis, except hindquarter amputation. It falls under the category “Anesthesia for Procedures on the Pelvis (Except Hip)” within the CPT code range maintained by the American Medical Association (AMA).

The distinction from hindquarter amputation is important. Hindquarter amputation (CPT code 01140, which covers interpelviabdominal amputation — removal of one half of the pelvis along with the entire lower limb) is a separate, adjacent code. CPT code 01150 applies specifically to radical tumor resections of the pelvis short of that amputation, including procedures such as internal hemipelvectomy and radical pelvic exenteration.

These are extensive oncologic surgeries performed under general or regional anesthesia. The complexity, operative duration, and patient acuity justify the higher base unit value relative to routine pelvic procedures. Anesthesiologists managing these cases should document patient positioning, monitoring requirements, and any intraoperative events carefully, as payers often scrutinize high-unit claims more closely.

Code category context

CPT code 01150 sits within a logical sequence of pelvic anesthesia codes. Understanding its neighbors helps coders avoid miscoding on similar procedures.

• CPT 01120: Anesthesia for procedures on the pelvis (general)
• CPT 01130: Anesthesia for body cast application or removal (not listed individually above but in range)
• CPT 01140: Anesthesia for interpelviabdominal (hindquarter) amputation
• CPT 01150: Anesthesia for radical procedures for tumor of pelvis, except hindquarter amputation
• CPT 01160: Anesthesia for closed procedures involving symphysis pubis or sacroiliac joint
• CPT 01170: Anesthesia for open procedures involving symphysis pubis or sacroiliac joint
• CPT 01173: Anesthesia for open repair, fracture disruption of pelvis

For surgical practices billing complex oncologic cases, having the adjacent code list documented in your billing workflow reduces the risk of choosing the wrong pelvis anesthesia code under time pressure.

Base units and time calculation

Anesthesia reimbursement uses a units-based formula rather than a direct fee. The total billable units for CPT code 01150 are calculated as:

Total Units = Base Units + Time Units + Qualifying Circumstance Units (if applicable)

CPT code 01150 carries 10 base units, confirmed by both the VA Community Care Table H (Professional Anesthesia Nationwide Base Units) and the Department of Labor Office of Workers’ Compensation Programs (DOL OWCP) fee schedule. This reflects the high complexity of radical pelvic tumor surgery relative to other pelvic procedures; for comparison, CPT 01160 carries 4 base units and CPT 01173 carries 12.

Time unit calculation

Most payers, including Medicare, calculate anesthesia time units in 15-minute increments. One time unit equals 15 minutes of continuous anesthesia time from induction to the patient’s emergence from anesthesia. A 4-hour case (240 minutes) therefore generates 16 time units, producing a total of 26 units when added to the 10 base units.

Some payers use different time intervals (such as 10- or 12-minute increments). Always verify the applicable payer’s anesthesia time unit convention before calculating claim totals, as the CMS Physician Fee Schedule provides the Medicare standard but commercial payers may differ.

Qualifying circumstances

Additional units may apply for qualifying circumstances under CPT codes 99100-99140. For example, CPT 99100 (anesthesia for patient under 1 year or over 70) adds 1 qualifying unit. Pelvic tumor patients are often elderly, making this a relevant qualifier for many CPT code 01150 claims.

Anesthesia modifiers

Modifier selection for CPT code 01150 is determined by who provides the anesthesia and how. Using the wrong modifier is one of the most common reasons anesthesia claims face denial or audit scrutiny.

• Modifier AA: Anesthesia services personally performed by an anesthesiologist. Used when the physician provides all anesthesia care without a CRNA or resident.
• Modifier QK: Medical direction of two to four CRNAs or anesthesiologist residents by an anesthesiologist.
• Modifier QX: CRNA service with medical direction by a physician. Appended to the CRNA’s claim when directed by an anesthesiologist billing QK.
• Modifier QZ: CRNA service without medical direction by a physician. Used when the CRNA works independently.
• Modifier QY: Medical direction of one CRNA by an anesthesiologist. Medicare-specific; applies when directing a single CRNA rather than a team of two to four.

For Medicare claims, the AA modifier produces full physician reimbursement. QK and QX split the unit value between the supervising anesthesiologist and the CRNA at 50% each. QZ pays the CRNA at the full conversion rate. Billing teams should confirm the supervision model documented in the anesthesia record before selecting a modifier, as discrepancies between the claim and the operative documentation trigger audits.

Physical status modifiers (P1 through P6) are added by some payers to reflect patient acuity. P3 and P4 are common for pelvic tumor patients given their underlying oncologic conditions. Not all payers reimburse additional units for physical status; verify with each payer before including them.

ICD-10 diagnosis code pairings

Every claim for CPT code 01150 requires a supporting ICD-10-CM diagnosis code that establishes medical necessity. The diagnosis must reflect the pelvic neoplasm or tumor condition prompting the radical surgical procedure. Common pairings fall into several groups.

Primary malignant neoplasms of the pelvis

• C19: Malignant neoplasm of rectosigmoid junction
• C20: Malignant neoplasm of rectum
• C51.0-C51.9: Malignant neoplasm of vulva
• C53.0-C53.9: Malignant neoplasm of cervix uteri
• C54.1: Malignant neoplasm of endometrium
• C56.1-C56.9: Malignant neoplasm of ovary
• C61: Malignant neoplasm of prostate
• C67.0-C67.9: Malignant neoplasm of bladder

Secondary and uncertain neoplasms

• C78.5: Secondary malignant neoplasm of large intestine and rectum
• C79.82: Secondary malignant neoplasm of genital organs
• D37.5: Neoplasm of uncertain behavior of rectum
• D39.0: Neoplasm of uncertain behavior of uterus

The diagnosis code must be specific enough to reflect the documented pathology. Coders using structured medical records with linked diagnostic entries reduce transcription errors between the clinical note and the claim. Always code to the highest level of specificity available in the documentation, particularly for laterality (when applicable) and histologic type.

The AAPC Codify CPT lookup provides a useful reference for crosswalking CPT anesthesia codes to relevant ICD-10 diagnosis codes by procedure type. For ICD-10-CM classification guidance at the definition level, the CDC/NCHS maintains the official U.S. code set and coding guidelines.

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Medicare and payer coverage

Medicare covers CPT code 01150 when the claim meets medical necessity criteria, the correct modifier is applied, and the supervising or performing provider is enrolled in Medicare. Reimbursement is calculated by multiplying total anesthesia units by the Medicare anesthesia conversion factor for the provider’s geographic locality.

Geographic payment locality matters for CPT code 01150. Practices in high-cost metropolitan areas will receive a higher dollar-per-unit conversion factor than rural providers. The CMS Physician Fee Schedule lookup tool at cms.gov allows you to search the exact conversion factor applicable to your locality for the current fiscal year.

Medicaid and state-level coverage variations

State Medicaid programs apply their own coverage policies and fee schedules, and their treatment of CPT code 01150 varies widely. Some state Medicaid programs and safety-net plans list the code as non-payable, while others cover it as billable, and the base-unit scale used can differ from the VA/DOL convention. Always confirm the current coverage status, base-unit scale, and conversion factor directly in the applicable state Medicaid provider manual before billing.

Always check the specific state Medicaid provider manual before submitting CPT code 01150 claims. Coverage status, unit scales, and prior authorization requirements vary by state and are updated periodically. Billing teams using compliance management software can configure payer-specific rules to flag these variations automatically before claim submission.

Prior authorization and medical necessity

Radical pelvic tumor surgery is a high-cost procedure. Many commercial payers require prior authorization before the anesthesia service, tied to authorization of the surgical procedure itself. Confirm with the patient’s plan whether the anesthesia authorization is bundled with the surgical authorization or must be obtained separately.

Medical necessity documentation should include the tissue diagnosis (biopsy pathology), surgical plan, and evidence of failed or contraindicated less-invasive alternatives where relevant. Claims for CPT code 01150 without supporting operative notes or anesthesia records are regularly denied on post-payment audit. The patient intake forms in Pabau support structured pre-procedure documentation that can be attached to the patient record before the claim is generated.

Documentation requirements

Thorough documentation is what protects a CPT code 01150 claim on audit. Inadequate documentation is the most common reason for post-payment recovery on anesthesia claims for complex surgical procedures.

Anesthesia record requirements

The anesthesia record must capture the following at a minimum:

• Patient’s ASA physical status classification (P1-P6)
• Anesthesia start and stop times (to support time unit calculation)
• Type of anesthesia administered (general, regional, monitored anesthesia care)
• Name and credentials of the anesthesiologist and any supervised CRNA or resident
• Continuous monitoring data (blood pressure, heart rate, oxygen saturation, temperature)
• Intraoperative events and interventions
• Patient emergence from anesthesia and transfer of care

For QK (medical direction) billing, additional documentation is required to evidence the anesthesiologist’s presence for induction, availability during the case, and involvement in emergence. Many payers request this during pre-payment or post-payment review. Practices that maintain structured claims management workflows can attach the anesthesia record directly to the claim at submission, reducing the back-and-forth on documentation requests.

Operative and surgical documentation

The anesthesia claim should be supported by the surgeon’s operative report confirming the procedure matches the CPT code 01150 descriptor. Specifically, the report should describe a radical procedure for pelvic tumor that falls short of hindquarter amputation. If the procedure involved hindquarter amputation, CPT 01140 is the correct code rather than 01150.

Pathology reports confirming the tumor diagnosis strengthen the ICD-10 pairing on the claim. Practices building HIPAA-compliant records management workflows for oncology patients should ensure the pathology note is linked to the patient’s surgical encounter before claim generation. For billing teams supporting multiple surgeons, cross-referencing the surgeon’s CPT code with the anesthesiologist’s CPT code 01150 claim catches procedure-to-anesthesia mismatches before submission.

Common denial reasons and how to avoid them

CPT code 01150 claims are denied for a predictable set of reasons. Recognizing these patterns reduces avoidable rework and speeds up reimbursement cycles.

• Wrong modifier: QK/QX claims denied because the anesthesiologist’s documentation doesn’t evidence all seven medical direction requirements under Medicare. Solution: Build a checklist that maps each medical direction requirement to the corresponding documentation field in the anesthesia record.
• Missing or mismatched ICD-10: Claim denied because the diagnosis code doesn’t support a radical pelvic procedure. Solution: Link the diagnosis code directly to the pathology and operative note at charge capture, not after the fact.
• Time unit calculation error: Reimbursement short-paid because minutes were rounded incorrectly. Solution: Use the anesthesia record’s documented start and stop times, not the surgeon’s incision-to-close time.
• Non-covered service (state Medicaid): Some state Medicaid or safety-net plans deny 01150 outright. Solution: Verify payer coverage before scheduling and confirm financial responsibility with the patient when the payer doesn’t cover the code.
• Procedure-anesthesia mismatch: Anesthesia claim for 01150 denied because the surgeon billed a hindquarter amputation code. Solution: Reconcile surgical CPT and anesthesia CPT codes before submission.

For practices billing anesthesia across multiple surgical specialties, the operational infrastructure supporting the billing team matters. A standardized denial management workflow catches these patterns across claim batches rather than managing each denial individually.

Related CPT codes for pelvic and oncologic anesthesia

Coding accuracy for CPT code 01150 benefits from familiarity with adjacent codes. See the full context of IVF CPT codes when managing a mix of gynecologic and oncologic anesthesia billing.

Adjacent code reference guides provide supporting context when billing teams need to cross-check anesthesia code selection against procedure type. The FastRVU 2026 RVU lookup also allows anesthesia billing teams to verify current Medicare reimbursement values for pelvic anesthesia codes against their geographic locality.

Conclusion

Radical pelvic tumor surgery presents one of the higher-complexity anesthesia billing scenarios, and CPT code 01150 claims are particularly vulnerable to denial when modifier selection, documentation, and ICD-10 pairing aren’t tightly managed. The 10 base unit value reflects clinical complexity, and getting reimbursement right requires equally rigorous billing process controls.

Pabau’s claims management software supports surgical and anesthesia billing teams with structured documentation workflows, diagnosis-to-procedure linking, and payer-specific rule configurations that reduce the denial rate on high-complexity claims like CPT code 01150. To see how Pabau handles radical pelvic tumor anesthesia billing, book a demo with the team.

Continue your research

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