CPT Code 00144: Eye Procedure Anesthesia Billing Guide

Anesthesia claims for corneal transplant surgery are billed under a single, specific CPT code: 00144. Despite sitting inside the eye anesthesia family (00140-00148), CPT 00144 is not a catch-all or fallback code — it has its own official descriptor, its own ASA base unit value, and its own set of supporting ICD-10 diagnoses tied to corneal disease.

Confusing it with the family’s actual not-otherwise-specified code, or with the sibling code for cataract surgery, is the single most common reason corneal transplant anesthesia claims get flagged in audit. This guide covers the correct base units, the reimbursement formula, modifiers, documentation requirements, and the ICD-10 and surgical CPT codes that support medical necessity for CPT code 00144.

Key Takeaways

CPT code 00144 describes anesthesia for a corneal transplant (keratoplasty) — a distinct, standalone code within the 00140-00148 eye anesthesia family, not an NOS or fallback code and not a “child” of CPT 00140.

The ASA Relative Value Guide assigns CPT 00144 a base unit value of 6, which forms the foundation of the reimbursement formula.

Correct billing requires a qualifier modifier (AA, QZ, QK, QX, or QY) on every claim; missing or incorrect modifiers are the most common reason for denial.

Practice management software like Pabau helps anesthesia and ophthalmic practices keep pre-anesthesia evaluations, operative notes, and diagnosis documentation organized and audit-ready.

CPT code 00144: definition and clinical description

CPT code 00144 describes anesthesia for procedures on the eye; corneal transplant, per the American Medical Association’s CPT code set. It is a distinct, billable code in its own right — not a fallback used whenever another eye anesthesia code fails to fit.

The eye anesthesia family covers six separately defined codes, each tied to a specific type of ocular surgery: 00140 is the family’s genuine not-otherwise-specified (NOS) code, 00142 covers lens (cataract) surgery, 00144 covers corneal transplant, 00145 covers vitreoretinal surgery, 00147 covers iridectomy, and 00148 covers ophthalmoscopy.

None of these codes is a “parent” or “child” of another — each stands on its own, with its own descriptor and base unit value.

The code sits within CPT section 00100-00222, which covers anesthesia for all procedures on the head. Accurate use of CPT 00144 depends on the operative note documenting an actual corneal transplant (keratoplasty) procedure — not a cataract extraction, vitrectomy, or another eye procedure with its own dedicated anesthesia code.

Payer auditors compare the anesthesia code on the claim against the surgical CPT code and the operative report, so the two must agree: an anesthesia claim for 00144 paired with a cataract-extraction surgical code is a mismatch that will draw scrutiny, not a matter of interpretation.

Anesthesiologists, CRNAs, and anesthesia billing teams working in ophthalmology practices encounter this code specifically for scheduled corneal transplant cases, including penetrating keratoplasty and endothelial keratoplasty procedures performed for corneal disease. This article covers base units, the reimbursement formula, modifiers, documentation requirements, and the ICD-10 and surgical CPT codes that support medical necessity for CPT code 00144.

CPT code 00144 reimbursement calculation

Anesthesia billing uses a time-based formula rather than a flat fee per procedure, and it is priced separately from the Medicare Physician Fee Schedule’s RVU methodology. Payment for CPT code 00144, like all anesthesia codes, is calculated as:

(Base Units + Time Units + Qualifying Circumstances Units) x Anesthesia Conversion Factor = Payment

Each component plays a distinct role in the final reimbursement amount.

Worked example: A 60-minute corneal transplant billed with CPT code 00144 on Medicare generates 4 time units (60 min / 15 min). Add 6 base units for a total of 10 units. At the CY2026 national non-APM anesthesia conversion factor of $20.4976, that’s approximately $204.98 before any locality adjustment (10 x $20.4976).

Traditional Medicare assigns qualifying circumstance codes 99100-99140 status indicator B, which bundles their value into the primary anesthesia code, so a 99100 add-on for a patient over age 70 does not create an 11th payable unit on a Medicare claim.

Under ASA Relative Value Guide methodology, or for a payer that recognizes qualifying circumstances as separately payable, the same case would total 11 units, or approximately $225.47 (11 x $20.4976).

Locality-specific anesthesia conversion factors are published in the CMS Anesthesiologists Center and the Physician Fee Schedule Final Rule Addenda D and E. Always verify the current-year locality figure and payer policy on qualifying circumstances before estimating payment.

Qualifying circumstances add-on codes

Qualifying circumstances codes (99100-99140) are listed in addition to the primary anesthesia code, not as a replacement for it. Under ASA Relative Value Guide methodology, each adds 1 unit to the calculation. Traditional Medicare assigns all four status indicator B, bundling their value into the primary anesthesia code rather than paying them as a separate unit.

CMS and most commercial payers recognize all four codes as valid add-ons, but recognition does not guarantee separate payment. Always verify payer policy before billing, since some local coverage determinations restrict qualifying circumstances add-ons for specific procedures.

Modifiers for CPT code 00144

Every anesthesia claim must carry a qualifier modifier identifying the provider type and supervision arrangement. Omitting the modifier, or using the wrong one, is the single most common cause of claim denial for CPT code 00144. CMS requires one of the following on every anesthesia claim submitted to Medicare.

CRNA billing for CPT 00144

CRNAs may bill CPT code 00144 independently using modifier QZ in states that have opted out of federal physician supervision requirements. When working under physician medical direction, the CRNA bills with QX while the directing anesthesiologist bills the same 00144 claim with modifier QK (for two to four concurrent cases) or QY (for one concurrent case).

Both the CRNA and the physician submit separate claims for the same procedure in a medically directed arrangement. CRNA scope of practice and supervision requirements vary by state; always verify applicable state law before selecting the modifier.

Documentation requirements for billing 00144

Missing documentation is the second-most common reason anesthesia claims fail post-audit. The anesthesia record itself must support every element of the billing formula, and for a corneal transplant case it must also tie to the specific keratoplasty procedure performed.

• Pre-anesthesia evaluation: completed and signed before the procedure, documenting the patient’s ASA physical status classification, relevant medical history, allergies, airway assessment, and planned anesthetic technique
• Intraoperative monitoring record: continuous vital signs with timestamps, medications administered with doses and times, anesthesia start time (induction), and anesthesia end time (emergence)
• Provider credentials: the anesthesia record must identify the performing provider by name and credentials (MD/DO or CRNA) and document the supervision arrangement if applicable
• Medical necessity: a signed surgical note confirming the corneal transplant (keratoplasty) procedure performed, including the graft type (anterior lamellar, penetrating, or endothelial) and lens status where relevant; the ICD-10 diagnosis code supporting the corneal condition must be present on the claim and traceable to the medical record
• Qualifying circumstances: if add-on codes 99100-99140 are billed, the clinical justification (patient age, emergency status, use of controlled hypotension) must appear in the record
• Post-anesthesia care unit (PACU) note: required by most payers; documents patient condition on arrival to recovery and discharge criteria met

Using digital intake forms integrated into the patient record reduces missing documentation by capturing structured pre-anesthesia data at the point of care rather than relying on retrospective note completion.

ICD-10 codes commonly paired with CPT 00144

Medical necessity for CPT code 00144 is established by the ICD-10-CM diagnosis codes on the claim, and for corneal transplant anesthesia those diagnoses need to reflect corneal pathology — not cataract, glaucoma, retinal, or macular disease, which support different codes in the 00140-00148 family.

Payer local coverage determinations (LCDs) vary; a diagnosis that supports 00144 for one MAC jurisdiction may not automatically satisfy another payer’s policy. The codes below represent common corneal-transplant pairings confirmed across multiple coding sources, but verify current LCDs before submission.

Surgical CPT codes billed alongside anesthesia code 00144

CPT 00144 is the anesthesia code; the surgeon reports a separate CPT code for the corneal transplant procedure itself. The surgical code selected depends on the graft technique and, for penetrating keratoplasty, the patient’s lens status — and it should agree with the ICD-10 diagnosis and the anesthesia claim.

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NCCI edits and bundling rules

The National Correct Coding Initiative (NCCI) establishes pairs of codes that cannot be billed together by the same provider on the same claim date. For anesthesia codes like 00144, the most relevant NCCI restrictions concern bundling the anesthesia code with other services that are considered integral to anesthesia care.

Accurate diagnosis code documentation at the claim level is one factor that reduces NCCI-related edits.

• Do not bill 00144 with monitored anesthesia care (MAC) management codes on the same day unless a distinct, separately identifiable service was provided and documentation supports the unbundling
• CRNA services and physician medical direction services cannot both be billed at 100% reimbursement for the same case; the medically directed arrangement splits the payment between the physician (QK/QY) and CRNA (QX)
• Qualifying circumstances codes (99100-99140) are add-on codes only and cannot be billed as standalone services; they require a primary anesthesia code on the same claim
• NCCI edits update quarterly; always verify the current NCCI tables on the AAPC’s CPT code reference or the CMS NCCI portal before billing edge-case scenarios

Related anesthesia CPT codes in the eye section

Selecting the correct code within the 00140-00148 family is critical. The codes are not interchangeable and are not arranged in a parent/child hierarchy — using CPT code 00144 when a more specific sibling code applies results in a coding error that can trigger audits or incorrect reimbursement.

Common billing errors and how to avoid them

Most denials on CPT code 00144 claims trace back to a handful of recurring mistakes. Correcting them before submission is far less costly than working denials after the fact.

• Confusing 00144 with the family’s NOS code, 00140: 00144 has its own specific descriptor — corneal transplant — and is not a fallback. If the operative report doesn’t document a corneal transplant, 00144 is the wrong code; check whether 00140 (the true NOS code), 00142 (lens surgery), or another sibling code applies instead.
• Missing or incorrect modifier: submitting 00144 without a qualifier modifier (AA, QZ, QK, QX, QY) is an automatic rejection under Medicare. Add the modifier before submission, not as a corrected claim.
• Wrong time unit calculation: some billers default to 15-minute intervals when the payer contract specifies 10-minute units. Check the payer contract before calculating time units; a systematic error here results in consistent underpayment.
• Unsupported ICD-10 pairing: billing 00144 with a diagnosis that doesn’t reflect corneal pathology — for example, a cataract or glaucoma code — is a mismatch that a payer’s LCD will not support. Pair the claim with a corneal diagnosis such as keratoconus, corneal edema, bullous keratopathy, corneal degeneration, corneal opacity, or a corneal transplant status/complication code.
• Failing to bill qualifying circumstances separately: add-on codes 99100-99140 must appear as line items on the claim with the primary anesthesia code also present. Submitting the add-on without the primary triggers an edit.
• Using the wrong anesthesia conversion factor: applying the standard (non-anesthesia) Physician Fee Schedule conversion factor, or an outdated figure, instead of the current-year anesthesia-specific conversion factor understates or overstates reimbursement. Anesthesia is not priced through the MPFS/RVU lookup path.

Practices that use practice management software like Pabau to keep structured documentation and diagnosis-to-procedure linkage in the patient record catch most of these errors before the claim leaves the practice, reducing the cost of rework and protecting reimbursement timelines. Reliable documentation habits applied at the point of care are the most sustainable way to maintain claim accuracy.

Payer-specific policies for CPT 00144

Medicare sets the baseline policy for CPT code 00144, but commercial payers frequently diverge on time unit intervals, qualifying circumstances coverage, and MAC billing requirements. Before billing a commercial plan, check the payer’s provider manual for their anesthesia-specific policies.

• Medicare: follows the CMS anesthesia payment formula — base units plus time units plus qualifying-circumstance units, multiplied by the anesthesia-specific conversion factor. Locality adjustments come from the Physician Fee Schedule Final Rule Addenda D and E and the CMS Anesthesiologists Center, not the work/PE/MP GPCI adjustments used for non-anesthesia codes. Medicare Administrative Contractors (MACs) publish local coverage determinations that list covered corneal diagnoses for keratoplasty anesthesia.
• Commercial payers: may use a contracted conversion factor different from Medicare’s. Some payers negotiate flat per-unit rates. Always reference the payer-specific fee schedule rather than assuming Medicare rates apply.
• Medicaid: reimbursement rules vary significantly by state. Some state Medicaid programs carve out anesthesia services to managed care plans; verify claim submission requirements with the relevant state agency.
• Workers’ compensation: typically uses state-specific fee schedules. The formula may differ from the CMS anesthesia formula; some workers’ compensation payers use a different base unit value or time unit interval.

For Medicare-specific anesthesia rate verification, the CMS Anesthesiologists Center and the Physician Fee Schedule Final Rule Addenda D and E provide the current-year, locality-adjusted anesthesia conversion factor. Always use the current-year figures; rates update annually on January 1.

Conclusion

CPT code 00144 is a precise, standalone code for corneal transplant anesthesia — not a fallback for eye procedures that don’t fit elsewhere.

Getting the modifier right, calculating time units against the correct base unit value (6, not 5), applying the current-year anesthesia conversion factor, and pairing the claim with a corneal ICD-10 diagnosis are the factors that most directly determine whether the claim pays on the first submission or enters the denial cycle.

Practice management software like Pabau helps anesthesia and ophthalmic practices keep pre-anesthesia evaluations, operative notes, and diagnosis documentation organized in one patient record, so the medical-necessity narrative is ready before a claim is submitted. Pabau supports the same practice management workflows across surgical specialties beyond ophthalmology.

That includes plastic surgery and hair transplant practices, where anesthesia and procedure coding carry the same precision requirements as corneal transplant billing.

Book a demo to see how Pabau keeps documentation audit-ready across specialties.

Continue your research

Need a quick anatomical reference before you code the operative note? This diagram of the eye maps the structures that keratoplasty and other ocular procedures involve.

Billing anesthesia for a nose or sinus procedure instead? 00160 is the equivalent code within the same head anesthesia section.

Documenting a different ophthalmic diagnosis? H47.43 covers optic chiasm disorders in the same ICD-10 eye and adnexa chapter.

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