CPT Code 01200: Anesthesia for closed hip joint procedures

Key Takeaways

CPT Code 01200 covers anesthesia for closed, non-arthroscopic hip joint procedures such as closed reduction and joint manipulation; arthroscopic hip procedures use CPT 01202 instead.

The code carries 4 base units, set by the American Society of Anesthesiologists (ASA) and adopted by CMS.

Reimbursement is calculated as (Base Units + Time Units) x Conversion Factor; missing a required modifier is the most common denial trigger.

Pabau’s claims management software helps anesthesia billing teams apply correct modifiers, track time units, and submit clean claims.

The official descriptor, published by the American Medical Association (AMA), reads: “Anesthesia for all closed procedures involving hip joint.” That wording is the key restriction. The code covers closed procedures only, and open procedures fall outside it and require separate anesthesia codes in the 01200-01274 range.

CPT Code 01200 at a glance

Quick-reference data for coders and billing staff verifying code selection before claim submission.

Knee procedures fall outside this category entirely, even though the knee sits on the same limb. Anesthesia for knee and popliteal artery work is billed under 01440 instead.

Procedures covered under CPT Code 01200

The “closed” qualifier is the key restriction. CPT Code 01200 applies when the surgeon performs the hip procedure without opening the joint capsule surgically, and without using an arthroscope. The most common procedures billed under this code include:

• Closed reduction of hip dislocation
• Closed reduction of hip fracture without internal fixation
• Manipulation of the hip joint under anesthesia
• Biopsy of the hip joint (closed/percutaneous approach)
• Aspiration of the hip joint under anesthesia

Arthroscopic hip procedures, diagnostic or therapeutic, are billed under CPT 01202 instead of CPT 01200 — see the related codes table below for the full breakdown.

Open procedures, including total hip arthroplasty and open reduction with internal fixation (ORIF), also fall outside CPT Code 01200. Those procedures require separate anesthesia codes such as 01214 (hip arthroplasty) within the same 01200-01274 range.

Anesthesia providers working with sports medicine practice workflows need the closed/open/arthroscopic distinction clearly flagged at the point of code selection, since payers audit this distinction routinely.

How anesthesia billing works: The base units and time units formula

Anesthesia reimbursement does not work like a standard procedure fee. Instead of a flat payment, payers calculate payment using a formula. According to the CMS Medicare Physician Fee Schedule, the standard formula is:

CPT Code 01200 base units

CPT Code 01200 carries 4 base units, as established by the American Society of Anesthesiologists (ASA) and adopted by CMS. Base units reflect the inherent complexity of providing anesthesia for a given procedure type, and they are fixed regardless of how long the case runs.

For reference, a minor procedure might carry 3 base units, while a complex cardiothoracic case may carry 20 or more.

The 4 base units for CPT Code 01200 apply uniformly across all payers that follow the ASA base unit table. Most commercial insurers and Medicare adopt these values directly, though some Medicaid programs use state-specific tables.

Verify against the private insurer fee schedules your practice accepts before assuming the ASA value applies. Understanding how base units interact with time-based billing rules for other procedure codes helps billers spot inconsistencies across claim types.

Time units in anesthesia billing

Under Medicare, one time unit equals 15 minutes of anesthesia time. A 60-minute closed hip manipulation generates 4 time units. Combined with the 4 base units for CPT Code 01200, that is 8 total units before the conversion factor is applied.

Worked example for a 45-minute case:

• Base units: 4
• Time units: 3 (45 minutes / 15 minutes per unit)
• Total units: 7
• Payment = 7 x [2026 CMS conversion factor for your locality]

Commercial payers may use different time increments (8-minute or 12-minute intervals are common). Always confirm the contracted interval before submitting claims. Ensuring HIPAA-compliant claims submission requires accurate time documentation in the patient record to support every time unit billed.

CPT Code 01200 fee schedule and reimbursement rates 2026

The 2026 Medicare reimbursement for CPT Code 01200 is determined by multiplying total anesthesia units by the locality-adjusted conversion factor.

CMS sets the national conversion factor annually, and the CMS Anesthesiologists Information Center is the authoritative source for the current figure by locality.

Because conversion factors vary by geographic locality, the dollar amount for a 60-minute CPT Code 01200 case in Los Angeles differs from the same case in rural Mississippi.

Third-party rate aggregators publish estimated ranges, but billing teams should verify current rates directly via the CMS Anesthesiologists Information Center before quoting payers or patients.

Medicare reimbursement for CPT 01200

For Medicare specifically, the payment formula uses the CMS-published anesthesia conversion factor for the practice’s locality. Anesthesia codes are not paid on standard work or practice-expense RVUs the way surgical codes are; base units are fixed at 4 for CPT Code 01200, so the only variable to verify by locality is the anesthesia conversion factor itself, via the CMS Anesthesiologists Information Center.

Anesthesia modifiers for CPT Code 01200

Every CPT Code 01200 claim must carry at least one anesthesia modifier. The modifier tells the payer who performed or supervised the anesthesia, which determines the applicable payment rate. Submitting without a modifier, or with the wrong one, is among the most common denial causes for this code.

Modifier selection depends on the anesthesia care team model and payer-specific policy. CMS rules around medical direction (QK/QX) require the directing physician to meet seven specific conditions during the concurrent cases. Failure to document those conditions can void the medical direction claim entirely.

Documentation requirements for CPT Code 01200

Anesthesia claims carry a heavier documentation burden than most procedure codes, and payers often request the underlying record before or after payment. For CPT Code 01200, four things need to be in the patient file every time:

• Anesthesia start and stop times: recorded precisely, not rounded, since the 15-minute time units are calculated directly from them.
• An operative report confirming closed-procedure status: the surgeon’s note must state the procedure was performed closed, and reflect any intraoperative conversion to open, which changes the CPT code.
• All seven CMS medical-direction conditions, when billing QK/QX: documented evidence that the physician performed the pre-anesthesia exam, prescribed the plan, participated in the most demanding portions, monitored at frequent intervals, stayed physically available, provided post-anesthesia care, and confirmed a qualified anesthetist for any out-of-plan tasks. Missing one can void the claim.
• Diagnosis documentation supporting the ICD-10 pairing: the billed diagnosis must trace back to the surgeon’s own documentation, not the anesthesiologist’s notes, and match the operative report.

Capturing these details at the point of care, rather than reconstructing them after a claim is flagged, is what keeps anesthesia documentation denials low.

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Related CPT codes in the 01200-01274 range

CPT Code 01200 sits at the start of the hip and upper leg anesthesia section. Selecting the right code from this range requires knowing whether the hip procedure is open or closed, and which specific anatomy is involved.

These coaching and evaluation codes follow similar documentation logic but apply to different anesthesia procedure types.

The distinction between 01200 (closed) and 01210 (open) is the single most important code selection decision in this range. CPT 01200 carries 4 base units while CPT 01210 carries 6, and payers audit the operative report to confirm procedure type before allowing either.

A closed-procedure claim billed under an open-procedure code, or vice versa, triggers a medical necessity review and potential recoupment.

Anesthesia codes for other lower-extremity procedures follow the same base-unit logic. 01500 covers lower leg artery procedures, and 01991 covers diagnostic and therapeutic nerve blocks — both carry their own base unit value and modifier requirements separate from CPT 01200.

ICD-10 diagnosis codes used with CPT Code 01200

Anesthesia claims must be paired with the correct ICD-10 diagnosis code to establish medical necessity. The diagnosis code comes from the ordering or operating surgeon’s documentation, not the anesthesiologist’s assessment, and codes such as M25.551 must trace back to that documentation to pass initial payer edits. Common ICD-10 codes linked to CPT Code 01200 claims include:

ICD-10 pairing is claim-specific and payer-dependent. The codes above represent common clinical scenarios, not a universally required list. Some payers publish Local Coverage Determinations (LCDs) that specify which ICD-10 codes support medical necessity for closed hip procedure anesthesia. Review the relevant LCD for each payer before submission.

Common billing errors and how to avoid them

Anesthesia billing for CPT Code 01200 has several well-documented failure points. Knowing them before claim submission is cheaper than appealing denials after the fact.

• Missing or incorrect modifier: Every CPT Code 01200 claim requires a qualifying anesthesia modifier (AA, QK, QX, etc.). A claim submitted without one will typically deny on first pass. Wrong modifier selection, such as QX without a paired QK on the physician claim, triggers a coordination error.
• Coding an open procedure as closed: If the surgeon converts a planned closed reduction or manipulation to an open procedure intraoperatively, CPT Code 01200 no longer applies. The anesthesiologist must recode to the appropriate open-procedure code. Operative notes must be reviewed before claim submission.
• Incorrect time unit rounding: Medicare uses 15-minute time units. Some practices round to the nearest unit rather than counting complete units, causing billing to differ from documented anesthesia time. Document start and stop times precisely.
• Stale conversion factor: Using a prior year’s conversion factor for 2026 claims results in systematic over- or underpayment. Update your fee schedule table at the start of each calendar year.
• Unbundling with the surgical CPT code: The surgical CPT code (e.g., closed reduction of a hip fracture) and the anesthesia CPT code are billed separately. Never combine them on the same line item or use the surgical code in the anesthesia claim.

Reviewing other specialty CPT codes alongside anesthesia codes helps billing teams spot cross-code documentation inconsistencies before payers do. Capturing anesthesia start and stop times digitally at the point of care, rather than reconstructing them after the fact, reduces time unit errors significantly.

How Pabau simplifies anesthesia billing and CPT Code 01200 management

Most anesthesia billing errors happen before the claim is ever submitted, in the documentation step. Practitioners recording anesthesia start/stop times on paper forms, selecting modifiers manually from a reference sheet, or reconciling CPT codes after the fact without system-level checks create the conditions for every error in the list above.

Practice management software like Pabau addresses this at the workflow level, with built-in claims management.

Rather than catching errors after submission, it builds validation into the pre-claim stage: code selection is guided by procedure type, modifier requirements surface automatically based on provider role, and time unit documentation ties directly to the appointment record.

For practices managing multiple concurrent anesthesia cases, including those pairing surgical care with physical therapy scheduling for post-procedure recovery, the multi-location reporting in Pabau’s practice management software makes it easier to track case-level billing accuracy across providers.

Conclusion

CPT Code 01200 is a technically straightforward code with a narrow and specific application: anesthesia for closed hip joint procedures. Getting it right depends on three things: confirming the procedure is closed, applying the correct modifier for the care team model, and calculating time units against the current year’s conversion factor.

Pabau’s claims management tools bring those three steps into a single connected workflow, reducing the manual checks that introduce errors at each stage.

The result is fewer first-pass denials and less time spent on appeals, which is where anesthesia billing costs mount fastest. See how Pabau handles it for your practice by booking a demo.

Continue your research

Need guidance on billing other specialty procedure codes? IVF CPT codes covers the coding and billing framework for reproductive medicine procedures, including time-based documentation requirements.

Need anesthesia coding guidance for a different joint? CPT Code 01400 covers anesthesia for knee joint procedures, the category CPT 01200 explicitly excludes.

Pairing a musculoskeletal diagnosis with an anesthesia claim? ICD-10 Code M60.9 covers unspecified myositis, a diagnosis that can support medical necessity for procedures in this coding family.

Frequently Asked Questions