CPT code 00144 describes anesthesia services provided to a patient undergoing a corneal transplant procedure, also known as keratoplasty. It falls within the AMA CPT anesthesia code range 00100–00222 (Anesthesia for Procedures on the Head) and is reported by the anesthesiologist or Certified Registered Nurse Anesthetist (CRNA) managing intraoperative anesthesia care — not by the operating ophthalmologist. Accurate use of this code requires understanding anesthesia unit calculation, physical status modifier selection, and provider delivery model modifiers, all of which directly affect claim payment under Medicare and commercial payers.
What Does CPT Code 00144 Mean?
CPT code 00144 is the designated anesthesia code for procedures on the eye involving corneal transplantation. The full AMA descriptor reads: Anesthesia for procedures on eye; corneal transplant. This code is billable when an anesthesia provider personally performs, medically directs, or supervises anesthesia for any form of keratoplasty — penetrating or lamellar — performed in an ambulatory surgical center (ASC) or hospital operating room.
Key attributes at a glance:
- Code category: Anesthesia / Head
- Billable by: Anesthesiologist (MD/DO), CRNA, or anesthesiologist assistant (AA)
- Applicable setting: ASC or hospital OR
- Base units: 6 base units (ASA Relative Value Guide)
- Billing method: Base units + time units + qualifying circumstance units × anesthesia conversion factor
- Global period: Not applicable — anesthesia codes do not carry surgical global periods
What Services and Procedures Does CPT 00144 Cover?
CPT 00144 applies to anesthesia services provided in connection with any corneal transplant surgical procedure. The specific keratoplasty technique performed by the surgeon determines which surgical CPT code is reported; CPT 00144 is used by the anesthesia team regardless of which transplant variant is performed.
Surgical procedures that drive a CPT 00144 anesthesia claim include:
- Penetrating keratoplasty (full-thickness corneal replacement)
- Anterior lamellar keratoplasty
- Deep anterior lamellar keratoplasty (DALK)
- Endothelial keratoplasty (DSAEK, DMEK)
- Keratoplasty for keratoconus, corneal scarring, Fuchs’ endothelial dystrophy, or bullous keratopathy
What Does CPT 00144 Specifically Exclude?
CPT 00144 does not cover anesthesia for all ophthalmic procedures. Coders and billers should note the following exclusions:
- Lens surgery (cataract procedures) → Use CPT 00142
- Vitreoretinal surgery → Use CPT 00145
- Iridectomy → Use CPT 00147
- Ophthalmoscopy or eye exam under anesthesia → Use CPT 00148
- General procedures on the eye, not otherwise specified → Use CPT 00140
- Any anesthesia for a corneal procedure that does not involve transplantation (e.g., corneal biopsy or superficial keratectomy) is not captured by 00144 and requires evaluation of the appropriate code under 00140 or the range of surgical eye codes
When Is CPT 00144 the Right Code to Use?
Selecting CPT 00144 is straightforward once you confirm that a corneal transplant — not another ophthalmic procedure — is the operative procedure being anesthetized. Apply the following decision criteria:
- Confirm the surgical CPT code on the operative report falls within the keratoplasty range (CPT 65710–65757 or related endothelial/lamellar codes).
- Confirm an anesthesia provider (anesthesiologist, CRNA, or AA) personally managed intraoperative anesthesia care.
- Confirm that anesthesia services were not strictly topical drops or procedural sedation administered by the surgeon alone — those scenarios do not generate a separate anesthesia claim.
- Confirm the procedure took place in an OR-equivalent surgical setting (ASC or hospital), not in an office-based procedure room.
- Select the appropriate physical status modifier (P1–P6) based on pre-procedure assessment documentation.
How Does CPT 00144 Differ From CPT 00140?
| Feature | CPT 00144 | CPT 00140 |
|---|---|---|
| Descriptor | Anesthesia; corneal transplant | Anesthesia; procedures on eye, NOS |
| Base units (ASA) | 6 | 5 |
| Clinical specificity | Keratoplasty only | Catch-all for unlisted eye procedures |
| When to use | Confirmed transplant procedure | Non-transplant eye procedures not covered by 00142–00148 |
| Audit risk if misused | Moderate — if 00140 is billed when transplant was performed | High — 00140 underbills vs. 00144 by 1 base unit |
In practice, anesthesia billing teams sometimes default to CPT 00140 for all ophthalmic cases when an anesthesiologist covers a mixed ophthalmology OR schedule. This is one of the most common underbilling errors in anesthesia revenue cycle management for eye surgery programs.
What Documentation Is Required to Support CPT 00144?
What Must the Anesthesia Provider Document in the Anesthesia Record?
The anesthesia record is the primary claim-support document for CPT 00144. A compliant record must contain:
- Pre-anesthesia evaluation note — ASA physical status (P1–P6) assessed and documented before the procedure
- Anesthesia start time — The moment the anesthesiologist begins preparing the patient for anesthesia in the operating room
- Anesthesia end time — The moment the patient is safely transferred to post-anesthesia care, ending the anesthesiologist’s personal attendance
- Anesthesia type — General anesthesia (most common for corneal transplant) or monitored anesthesia care (MAC), documented explicitly
- Provider identity and role — Identification of the performing anesthesiologist, CRNA, or AA, and documentation of whether medical direction or supervision was applied
- Intraoperative monitoring documentation — Vital signs, ventilation, and hemodynamic parameters throughout the procedure
- ICD-10-CM diagnosis code support — A linked diagnosis that establishes medical necessity for the transplant (e.g., H18.50x for unspecified hereditary corneal dystrophies, H18.812 for corneal disease left eye, or T86.84x for corneal transplant complications)
What Are the Documentation Standards for Facility vs. Non-Facility Settings?
| Documentation Element | ASC Setting | Hospital Inpatient/Outpatient |
|---|---|---|
| Pre-anesthesia evaluation | Required — same day or prior day | Required |
| Anesthesia record | Required | Required |
| Post-anesthesia note | Required within 30 minutes of PACU arrival | Required |
| Medical direction documentation | Required if QK/QX/QY applied | Required — must document all 7 required medical direction steps per CMS |
| Facility anesthesia billing | Facility does not separately bill 00144; only professional anesthesia provider bills | Hospital outpatient bills facility component separately; professional bills 00144 |
Per the CMS Medicare Claims Processing Manual (Chapter 12, Section 50), an anesthesiologist claiming medical direction reimbursement must document completion of all seven required steps — including pre-anesthesia evaluation, remaining immediately available, and completing the post-anesthesia visit — for each medically directed case.
How Does CPT 00144 Affect Medical Billing and Reimbursement?
Anesthesia billing operates on a base units + time units model rather than standard RVU-based billing used for surgical or E&M codes. The total payment formula is:
(Base Units + Time Units + Qualifying Circumstance Units) × Anesthesia Conversion Factor = Allowed Amount
CPT 00144 Anesthesia Unit & Reimbursement Overview
| Component | Value / Rate |
|---|---|
| Base units (ASA) | 6 |
| Time unit increment | 1 unit per 15 minutes of anesthesia time |
| Example: 90-minute procedure | 6 base units + 6 time units = 12 total units |
| Medicare anesthesia CF (2024, national approx.) | ~$21.99 per unit |
| Illustrative Medicare payment (90 min, P1, no qualifying circumstance) | ~$263.88 (12 × $21.99) |
| Physical status P3 addition | +1 unit (total 13 units → ~$285.87) |
| Qualifying circumstance 99100 (patient >70 yrs) | +1 unit |
Note: Actual Medicare allowed amounts vary by geographic locality. Providers should verify current rates via the CMS Physician Fee Schedule lookup tool for their specific MAC jurisdiction.
What Modifiers Are Commonly Used With CPT 00144?
| Modifier | Description | When to Apply |
|---|---|---|
| AA | Anesthesiologist personally performing | Anesthesiologist personally performs all anesthesia services |
| QK | Medical direction of 2–4 CRNAs | Anesthesiologist simultaneously directs 2–4 CRNA cases |
| QX | CRNA with physician medical direction | Billed by CRNA when under anesthesiologist’s direction |
| QY | Medical direction of one CRNA | Anesthesiologist directing a single CRNA |
| QZ | CRNA without physician direction | CRNA performing independently, no supervising physician |
| QS | Monitored anesthesia care (MAC) | When MAC — not general anesthesia — is provided |
| P1–P6 | ASA physical status | Always required; P1 = healthy, P6 = brain-dead donor |
| 99100 | Qualifying circumstance: patient <1 yr or >70 yrs | Add-on for age-related anesthesia risk |
| -23 | Unusual anesthesia | Used when general anesthesia is required for a procedure typically done under local (rare for keratoplasty) |
Are There Any Prior Authorization, Coverage Restrictions, or LCD Requirements?
- Most Medicare and commercial payers cover CPT 00144 when medical necessity for the corneal transplant is documented in the surgical record.
- Medicare Advantage plans may require prior authorization for the surgical procedure; the anesthesia claim cannot be submitted without the surgical claim, so PA delays on the surgical side will cascade to the anesthesia claim.
- Some payers restrict reimbursement for MAC (modifier QS) for corneal transplants, preferring general anesthesia coverage only. Verify local coverage determinations (LCDs) with your MAC.
- When a patient is over 70 years old, qualifying circumstance code 99100 should be added to capture the additional complexity unit and ensure it is not omitted.
What CPT or HCPCS Codes Are Commonly Billed Alongside CPT 00144?
The anesthesia provider bills CPT 00144 independently from the surgeon’s claim. The following codes are frequently found on the surgical claim for the same date of service, creating a multi-provider claim scenario that billers must understand.
| Associated Code | Description | Typical Context | Bundling Risk |
|---|---|---|---|
| 65730 | Penetrating keratoplasty (PKP) | Most common full-thickness transplant | No — separate provider bills |
| 65756 | Endothelial keratoplasty (DSAEK) | Fuchs’ dystrophy, bullous keratopathy | No — separate provider bills |
| 65710 | Anterior lamellar keratoplasty | Keratoconus, stromal disease | No — separate provider bills |
| 65755 | Penetrating keratoplasty with cataract | Concurrent cataract + transplant | Moderate — anesthesia code remains 00144 |
| 99100 | Qualifying circumstance (age) | Patient >70 or <1 year | Not a bundling risk; add-on to 00144 |
| 99140 | Qualifying circumstance (emergency) | Urgent/emergent transplant | Add-on when applicable |
Which Code Combinations Trigger NCCI or CCI Edits?
CPT 00144 itself is generally not subject to NCCI edit conflicts because it is an anesthesia code billed by a different provider than the surgeon. However, billing teams should watch for:
- Duplicate anesthesia claims: If both an anesthesiologist and CRNA bill for the same case without consistent medical direction modifiers, the second claim will be denied. Ensure modifier pairing is consistent (QK on physician claim + QX on CRNA claim).
- Unbundling pre-anesthesia evaluation: A pre-operative E&M service billed on the same date by the anesthesiologist is generally bundled into the anesthesia service unless it is a separate, distinct visit on a prior calendar date.
What Coding Errors Should You Avoid With CPT 00144?
In practice, anesthesia billing teams encounter a predictable set of errors on keratoplasty claims. The following are ranked by audit and denial frequency:
- Using CPT 00140 instead of 00144 — Defaulting to the general eye code costs 1 base unit per claim and represents systematic underbilling across an eye surgery program.
- Omitting the physical status modifier — Claims submitted without a P-modifier (P1–P6) will reject or reprocess at the lowest allowable rate under many payers.
- Incorrect time calculation — Anesthesia time begins when the provider starts preparation of the patient for anesthesia in the OR, not at surgical incision. Using incision-to-close times consistently undercounts billable time.
- Mismatched medical direction modifiers — Submitting QK on the physician claim but QZ on the CRNA claim for the same case triggers an automatic denial on the second claim processed.
- Missing qualifying circumstance code 99100 — Corneal transplant patients are frequently elderly (Fuchs’ dystrophy is common in patients over 65). Missing 99100 for patients over 70 leaves one unit of reimbursement on the table per case.
- No MAC documentation when QS is used — If modifier QS is applied, the anesthesia record must clearly document that MAC — not general anesthesia — was the intended and delivered service type.
What Do Auditors and RAC Reviewers Look for When Reviewing Claims With CPT 00144?
- Anesthesia record timestamps for start/end time that are inconsistent with the surgical operative report
- Physical status modifier assigned (e.g., P1) that is inconsistent with the patient’s documented comorbidities in the pre-anesthesia evaluation
- Claims where the anesthesiologist bills AA (personally performing) while separately billing QK for concurrent cases on the same date
- Missing post-anesthesia visit note when billing under medical direction modifiers (required by CMS for full medical direction reimbursement)
- Use of modifier -23 (unusual anesthesia) without operative note documentation explaining why general anesthesia was medically necessary for this patient
How Does CPT 00144 Relate to Other CPT Codes?
Understanding CPT 00144’s position within the anesthesia code family — and its relationship to the surgical codes it accompanies — is essential for accurate claim pairing.
| Related Code | Relationship Type | Key Distinction |
|---|---|---|
| 00140 | Sibling — same family, lower specificity | General eye anesthesia; fewer base units (5 vs. 6) |
| 00142 | Sibling — parallel eye code | Lens surgery/cataract anesthesia; different surgical trigger |
| 00145 | Sibling — parallel eye code | Vitreoretinal surgery anesthesia |
| 00147 | Sibling — parallel eye code | Iridectomy anesthesia |
| 65730 / 65756 | Surgical companion code | These are the surgical codes that prompt use of 00144 |
| 99100 | Qualifying circumstance add-on | Added when patient is >70 or <1 year old |
| 99140 | Qualifying circumstance add-on | Emergency conditions — add to 00144 when applicable |
What Is the Correct Code Sequencing or Reporting Order When CPT 00144 Appears With Other Codes?
- Report CPT 00144 as the primary anesthesia code on the claim.
- Append the physical status modifier (P1–P6) immediately after the code (e.g., 00144-P2).
- Append the provider/delivery model modifier (AA, QK, QX, QY, or QZ) as the second modifier.
- Report 99100 or 99140 as separate line items (add-on codes) when qualifying circumstances apply — do not append them as modifiers to 00144.
- On the anesthesia claim, report anesthesia start and end time in the appropriate claim field (Box 24F time fields on CMS-1500, or the equivalent EDI loop).
Real-World Coding Scenario — How CPT 00144 Is Applied in Practice
Patient encounter: A 74-year-old female with Fuchs’ endothelial corneal dystrophy presents for DSAEK (Descemet stripping automated endothelial keratoplasty) on the left eye. The anesthesiologist documents a P2 physical status (mild controlled hypertension) in the pre-anesthesia evaluation. General anesthesia is administered. Anesthesia start time: 8:04 AM. Anesthesia end time: 9:49 AM. Total anesthesia time: 105 minutes = 7 time units.
Correct Code Application
- Surgical claim (ophthalmologist): CPT 65756-LT (endothelial keratoplasty, left eye)
- Anesthesia claim (anesthesiologist, personally performing):
- CPT 00144-P2-AA (corneal transplant anesthesia, physical status P2, personally performing)
- Add-on: 99100 (qualifying circumstance — patient age 74, over 70)
- Total anesthesia units: 6 (base) + 7 (time) + 1 (P2 modifier unit) + 1 (99100) = 15 units
- Illustrative Medicare payment: 15 units × ~$21.99 CF = ~$329.85
Common Mistake in This Scenario
- Incorrect coding: CPT 00140-P2-AA + 99100 (using the general eye code instead of 00144)
- Why it fails: CPT 00140 carries only 5 base units vs. 00144’s 6 base units. Total units would be 14 instead of 15, resulting in systematic underpayment. This error is particularly costly in high-volume corneal transplant programs.
- Second common mistake: Omitting 99100 for this 74-year-old patient — leaves 1 full unit of reimbursement uncaptured per case.
Frequently Asked Questions About CPT Code 00144
Is CPT Code 00144 Still Valid for Use in 2025?
CPT code 00144 remains a valid, active anesthesia code in the current AMA CPT code set with no descriptor changes for 2025. Anesthesia billing professionals should verify annually against the AMA CPT Professional Edition and the CMS Physician Fee Schedule to confirm any adjustments to the anesthesia conversion factor or associated qualifying circumstance codes.
How Many Base Units Does CPT 00144 Have?
CPT 00144 carries 6 base units per the ASA Relative Value Guide. This is higher than the general ophthalmic anesthesia code 00140 (5 base units), reflecting the greater complexity and longer operative duration typically associated with corneal transplantation compared to routine eye procedures.
What ICD-10-CM Diagnosis Codes Are Used With CPT 00144?
The diagnosis code reported on the anesthesia claim should match the surgical claim’s primary diagnosis. Common ICD-10-CM codes paired with CPT 00144 include H18.50 (hereditary corneal dystrophy, unspecified), H18.812 (corneal disease, left eye), H16.xx (keratitis variants), and T86.841 (corneal transplant failure). The diagnosis must establish medical necessity for the transplant procedure itself.
Does the Anesthesia Type (General vs. MAC) Affect How CPT 00144 Is Billed?
The anesthesia type does not change the CPT code itself — 00144 is reported regardless of whether general anesthesia or monitored anesthesia care (MAC) is used. However, if MAC is the service delivered, modifier QS must be appended to the claim to accurately identify the type of anesthesia service. Some payers restrict MAC coverage for corneal transplants; always verify the payer’s local coverage determination (LCD) before submitting a MAC claim.
Can a CRNA Bill CPT 00144 Without an Anesthesiologist?
Yes, a CRNA may bill CPT 00144 independently when operating without physician medical direction, using modifier QZ. Under Medicare, a CRNA billing with QZ is reimbursed at the same rate as an anesthesiologist. However, some states require physician involvement by law, and certain facilities restrict independent CRNA practice — always confirm state scope-of-practice laws and facility credentialing rules before assuming independent billing eligibility.
What Is the Difference Between CPT 00144 and CPT 00142?
CPT 00144 covers anesthesia for corneal transplant procedures (keratoplasty), while CPT 00142 covers anesthesia for lens surgery such as cataract extraction. The critical distinction is the surgical procedure being anesthetized — if the surgeon’s operative report documents a transplant of the cornea, use 00144; if the procedure is cataract or lens-based, use 00142. These are mutually exclusive codes that reflect entirely different ophthalmic surgeries.
How Is Anesthesia Time Calculated for CPT 00144 Claims?
Per AMA CPT anesthesia guidelines, anesthesia time begins when the anesthesiologist starts preparing the patient for anesthesia in the operating room and ends when the patient may be safely placed under post-operative supervision. Time is reported in 15-minute increments (1 unit per 15 minutes). A 90-minute anesthesia duration equals 6 time units, which are added to the 6 base units for CPT 00144 to produce 12 total units before applying any physical status or qualifying circumstance additions.
Key Takeaways for Billing and Coding CPT 00144
- CPT 00144 applies exclusively to anesthesia for corneal transplant (keratoplasty) — not cataract, vitreoretinal, or general eye procedures.
- The code carries 6 ASA base units, one unit more than the general eye anesthesia code 00140.
- Physical status modifier (P1–P6) is always required and directly adds to total reimbursable units.
- For patients over 70, always add qualifying circumstance code 99100 — omitting it is one of the most common underbilling errors in ophthalmic anesthesia.
- Provider model modifiers (AA, QK, QX, QY, QZ) are required to correctly identify whether an anesthesiologist personally performed, medically directed, or supervised CRNA services — and mismatched modifiers between co-billing providers will trigger claim denial.
- Anesthesia time begins at patient preparation in the OR, not surgical incision — using incision-to-close time consistently undercounts billable minutes.
- Verify current anesthesia conversion factors for your MAC jurisdiction via the CMS Physician Fee Schedule, as rates adjust annually and vary by geographic locality.
