CPT code 01212: Anesthesia for hip disarticulation

Key takeaways

CPT code 01212 covers anesthesia for open hip joint procedures that involve hip disarticulation, and carries 10 base units.

Payment equals base units plus time units plus modifying units, multiplied by the CMS conversion factor.

Modifiers AA, QX, QY, QZ, QS, and AD each describe a different supervision arrangement.

Report 01212 only when the operative report documents disarticulation, since total hip replacement is 01214.

Practice management software like Pabau routes each anesthesia invoice to the right insurer from the patient record.

CPT code 01212: definition, base units, and clinical use

CPT code 01212 is the anesthesia code for open hip joint procedures that involve hip disarticulation. It carries 10 base units, more than the general hip code and the hip replacement code.

Reporting it correctly comes down to two details. The first is whether the operative report documents disarticulation rather than a replacement or an arthroscopy. The second is which modifier matches the supervision arrangement in the room.

Payment then follows the anesthesia formula rather than a flat fee. The 10 base units are fixed, but time units are counted in 15-minute increments. An imprecise anesthesia record costs you units on every case.

Official descriptor and clinical context

The official descriptor for CPT code 01212, maintained by the American Medical Association (AMA) CPT Editorial Panel, is:

Hip disarticulation is a major amputation at the hip joint that removes the entire lower extremity. Malignant tumors of the femur or proximal soft tissue are the usual indication. Severe trauma and failed revascularization are the others. When the surgery is the revascularization attempt itself, the anesthesia code is 01270.

The physiologic demands are far greater than a routine hip arthroplasty, which is why 01212 carries more base units than the general hip code. Two neighboring codes describe similar amputations. Use 01404 for knee disarticulation and 01140 for hindquarter amputation.

The code sits in the anesthesia subsection for procedures on the pelvis and hip joint. Practices that bill hip surgery see the same handful of codes on every schedule. Keeping their descriptors side by side saves the coder a lookup.

Anesthesia base units for CPT 01212

Base units are the fixed component of anesthesia payment. They reflect the complexity of the procedure and the physiologic demands placed on the anesthesia provider.

CPT 01212 carries 10 base units. Confirm the figure against the current AMA CPT codebook or the CMS anesthesia base unit file before billing, since annual updates can revise it. The CMS Anesthesiologists Center publishes the current file.

Choosing between 01210 and 01212 is the most common decision in hip cases. The test is whether the surgery involves disarticulation. A total hip arthroplasty or any other hip joint procedure without disarticulation takes 01214 or 01210 instead.

How anesthesia reimbursement is calculated

Medicare pays anesthesia services on a formula rather than a flat fee. The formula is set out in the CMS Medicare Claims Processing Manual, Chapter 12:

Payment = (Base Units + Time Units + Modifying Units) x Conversion Factor

Each component works as follows:

• Base units (B): Fixed at 10 for CPT 01212. They reflect the complexity of the procedure.
• Time units (T): One unit per 15 minutes of anesthesia time. A 90-minute case generates six time units.
• Modifying units (M): Added when a qualifying circumstances code such as 99100 or 99140 is reported alongside the primary code.
• Conversion factor (CF): The dollar value per anesthesia unit, set each year by CMS. Check the current figure in the CMS Physician Fee Schedule tool. Conversion factors vary by year and by locality.

Worked example for a 90-minute hip disarticulation case

Payment varies by Medicare Administrative Contractor (MAC) region and by geographic practice cost index (GPCI). Pull the locality-specific rate from the CMS Physician Fee Schedule tool before you submit. A national average is not a billing figure.

Anesthesia modifiers and when to use them

Anesthesia modifiers tell the payer who performed or supervised the service. Modifier choice for a CRNA arrangement is one of the most audited areas in anesthesia billing. CMS sets the rules in the Medicare Claims Processing Manual, and individual MACs publish local guidance on top of them.

Check the modifier while the anesthesia record is still open, not at the end of the month. An AA claim billed where QX applied invites a compliance audit and a repayment demand.

Qualifying circumstances codes that add units

Qualifying circumstances are add-on codes reported alongside the primary anesthesia code. They apply when a patient or situational factor increases the complexity of the service, and they add modifying units to the payment formula.

Code 99100 is the qualifying circumstance most often reported with hip disarticulation, since many of these patients are over 70. Document the qualifying condition in the anesthesia record so the add-on code holds up on review.

ICD-10-CM diagnosis codes that support medical necessity

The ICD-10-CM diagnosis code paired with 01212 is what supports medical necessity. Hip disarticulation is performed for a limited set of indications, so the diagnosis has to justify the procedure in the operative report.

Verify every code against the FY2026 tables before submission, using the CDC ICD-10-CM tool or your encoder. Codes are updated each year, and some descriptors change between fiscal years.

Two details decide whether the pairing holds. Hip diagnosis codes are side-specific, the way M91.91 names the right leg. Injury codes also need the correct seventh character, as S33.4XXD shows for a subsequent encounter.

ASC payment status and place of service

CPT code 01212 is generally classified as not separately payable in the ambulatory surgical center (ASC) setting. Published ASC status indicators flag the code that way. Hip disarticulation is a high-acuity procedure performed in a hospital operating room rather than an outpatient ASC.

Verify ASC payability against the current CMS payment indicator tables before you submit. CMS updates those indicators each year in the Outpatient Prospective Payment System (OPPS) final rule, and a code’s status can change.

Place of service therefore decides whether the claim pays at all. This code also stops at the operating room door. Prosthetic fitting and rehabilitation are billed by the physical therapy team. Mobility equipment such as E0154 is billed separately as durable medical equipment.

Related CPT codes for hip and lower extremity anesthesia

Hip anesthesia codes sit in a tight range, and the surgical procedure decides which one applies. Reporting 01212 for a total hip replacement will not always trigger a denial. It does leave the documentation inaccurate and the claim exposed on audit.

The differentiator between 01210 and 01212 is the procedure itself, and 01212 is reserved for hip disarticulation. Total hip arthroplasty uses 01214, and revision arthroplasty uses 01215. Cross-check any unfamiliar descriptor in a CPT code lookup before the claim goes out.

The same logic runs down the leg, so 01360 covers open distal femur procedures and 01232 covers amputation of the femur. When the operative report does not say disarticulation, 01212 is the wrong code.

How Pabau keeps anesthesia claims accurate

Anesthesia billing has more moving parts than most procedure billing. Three variables feed the payment formula. The modifier depends on who was in the room, and the diagnosis has to justify the procedure on every claim.

In most practices those checks happen after the fact. A biller reads the anesthesia record days later, works out the time units by hand, then keys the insurer details into a separate system. Errors surface weeks afterwards as a denial.

Practice management software like Pabau keeps the record and the claim in one place instead. Anesthesia times and consent are captured as digital intake forms at the point of care. The biller then works from a complete note rather than a reconstruction.

From there, Pabau’s claims management tools take over. The insurer and policy sit on the patient record, so each invoice routes to the right payer without re-keying. Claims go out electronically through Claim.MD in the US, with eligibility checks and status tracking in one dashboard.

The outcome is fewer rejections from missing details and less time spent chasing them. Practices running regenerative medicine software see the same benefit on joint injections such as 20604, where modifier questions come up just as often.

Send every anesthesia claim from one dashboard

Pabau keeps the anesthesia record, the invoice, and the insurer in the same system, so claims go out complete. See how practices track every claim from submission to payment.

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Conclusion

Most 01212 errors trace back to the operative report rather than the code set. The descriptor looks like four of its neighbors, so the note has to say disarticulation before the claim goes out.

Practices that build that check into the workflow spend less time on appeals and see fewer surprises at month end. The trade-off is worth remembering. Verification takes two minutes, and an appeal takes half an hour.

Keeping the anesthesia record, the invoice, and the insurer in one system removes most of the re-keying that causes rejections. Book a demo to see how Pabau handles anesthesia claims from documentation through to payment.

Continue your research

Billing the surgeon’s side of the same case? 27130 covers total hip arthroplasty billing, from documentation through to the global period.

Coding an amputation of the upper limb? 01636 sets out the anesthesia rules for forequarter amputation, the shoulder equivalent of this procedure.

Hip procedure with no matching descriptor? 27299 explains how to document an unlisted pelvis or hip joint procedure so it still pays.

Billing anesthesia for a knee case next? 01400 walks through the anesthesia code for knee joint procedures and its base units.

Working through other orthopedic claims? 20150 covers excision of an epiphyseal bar, including the documentation payers look for.

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