Anesthesia billing hinges on base-unit capture, time-unit calculation from documented start/stop, CRNA direction modifiers (AA, QK, QX, QZ), and physical-status P1-P6 add-ons. General billers under-capture documented time and misapply direction rules on every case. MedFactor delivers anesthesia-specific RCM that protects every unit.
From general surgical and cardiothoracic to obstetric, pediatric, and regional anesthesia, we tailor billing to the unit-calculation and direction rules of every anesthesiology subspecialty.
Upper/lower abdomen (00790/00840), extremity, and routine surgical anesthesia with accurate base-unit and time-unit capture per ASA guide.
Heart and great-vessel cases (00560 family), pump oxygenator codes, and complex thoracic anesthesia with high base-unit accuracy.
Labor neuraxial analgesia (01967), cesarean delivery (01961), and the 01968 conversion add-on with correct time-unit determination.
Age-based anesthesia coding, qualifying circumstances (99100), and physical-status modifiers for neonatal and pediatric cases.
Regional blocks, MAC (QS/G8/G9), and interventional radiology anesthesia (01916-01933) with correct base-unit assignment.
QS, G8, and G9 modifier application, MAC versus moderate sedation distinction, and time-unit capture for monitored cases.
Anesthesia reimbursement is calculated as (Base Units + Time Units) × Conversion Factor. Base units are fixed per code; time units are documented minutes divided by the payer’s time increment. Under-capturing documented time is the single largest source of anesthesia revenue leakage.
Each anesthesia CPT carries a fixed ASA base-unit value. Time units come from the anesthesia record — documented start/stop time divided by 15 minutes (Medicare’s unit).
Anesthesia billing is governed by time-unit calculation, base-unit assignment, CRNA direction modifiers, and physical-status add-ons that general billing companies cannot navigate effectively.
Documented start/stop time not converted to 15-minute time units, dropping the time-component of reimbursement on every case.
Wrong base-unit value applied for the anesthesia CPT, understating the fixed complexity portion of the claim.
AA, QK, QX, or QZ applied incorrectly, triggering wrong payment rate or denial for medical-direction vs. independent CRNA cases.
P3-P6 physical-status modifiers not reported, losing qualifying-circumstance base units on complex patients (commercial payers).
Medical-direction cases exceeding the 4-procedure concurrency limit, invalidating the QK direction payment model.
Anesthesia record incomplete or missing documented start/stop times, causing time-unit and full claim denials.
Quick reference for the most frequently used anesthesia CPT, ICD-10, and modifier codes in anesthesiology billing and coding.
| Code | Description | Common Use |
|---|---|---|
| 00790 | Anesthesia, intraperitoneal upper abdomen incl. laparoscopy; NOS | Upper-abdomen laparoscopy (base 7) |
| 00840 | Anesthesia, intraperitoneal lower abdomen incl. laparoscopy; NOS | Lower-abdomen laparoscopy (base 6) |
| 00560 | Anesthesia for heart, pericardial sac & great vessels without pump | Cardiac / great-vessel surgery (base 15) |
| 01961 | Anesthesia for cesarean delivery only | Planned cesarean section (base 7) |
| 01967 | Neuraxial labor analgesia/anesthesia, planned vaginal delivery | Labor epidural management |
| 01968 | Anesthesia for cesarean following neuraxial labor analgesia (add-on) | Conversion to cesarean (with 01967) |
| 01916 | Anesthesia for diagnostic radiological procedures (arteriography/venography) | Diagnostic radiology anesthesia (base 5) |
| 01716 | Anesthesia for biceps tenodesis, upper arm | Upper-arm / shoulder procedure (base 5) |
| 00300 | Anesthesia for procedures on head, neck & posterior trunk; NOS | Head/neck NOS anesthesia |
| 01996 | Daily hospital management of epidural/subarachnoid drug administration | Post-op pain management (base only) |
| Code | Description | Clinical Context |
|---|---|---|
| Z01.818 | Encounter for other preprocedural examination | Preop evaluation NOS |
| Z01.810 | Encounter for preprocedural cardiovascular examination | Preop cardiac risk evaluation |
| O82 | Encounter for cesarean delivery without indication | Cesarean anesthesia |
| K80.20 | Calculus of gallbladder without cholecystitis, without obstruction | Cholecystectomy indication |
| K35.90 | Acute appendicitis without perforation | Appendectomy indication |
| I25.10 | Atherosclerotic heart disease without angina | Cardiac preop / risk |
| M54.5 | Low back pain | Spine imaging / pain procedure |
| J45.909 | Unspecified asthma, uncomplicated | Preop airway / anesthesia risk |
| E11.9 | Type 2 diabetes mellitus without complications | Preop metabolic comorbidity |
| Modifier | Description | Anesthesia Application |
|---|---|---|
| AA | Anesthesia personally performed by anesthesiologist | 100% personally performed service |
| QK | Medical direction of 2-4 concurrent anesthesia procedures | Medical direction (anesthesiologist) |
| AD | Medical supervision of more than 4 concurrent cases | Medical supervision (3 base-unit cap) |
| QX | CRNA service with medical direction by anesthesiologist | CRNA under direction |
| QY | Medical direction of one CRNA by anesthesiologist | Anesthesiologist directs one CRNA |
| QZ | CRNA service without medical direction | CRNA independent (no direction) |
| 23 | Unusual anesthesia | Anesthesia not usually required |
| 47 | Anesthesia by surgeon | Surgeon administers anesthesia (rare) |
| P3 | ASA physical status 3 — severe systemic disease | Qualifying circumstance, adds base units (commercial) |
| QS | Monitored anesthesia care (MAC) | MAC service (with G8/G9 for complex) |
Comprehensive revenue cycle management designed specifically for anesthesiology practices and CRNA groups.
Specialty coders calculate base units plus documented time units, apply direction modifiers (AA/QK/QX/QY/QZ), and capture P3-P6 status for every case.
Time-unit under-billing defense, direction-modifier corrections, and appeals backed by anesthesia-record start/stop documentation.
Anesthesia record review for documented start/stop time, P-status support, and concurrency tracking that backs every claim on audit.
Medical-direction (QK/QX/QY) vs. independent (QZ) and supervision (AD) modeling configured to your practice’s actual CRNA arrangement.
Prioritized follow-up on aged anesthesia claims with strategic payer escalation to recover time-unit and direction-modifier revenue.
Real-time dashboards tracking anesthesia units billed, time-unit capture rate, CRNA direction mix, and conversion-factor performance.
Understanding the most common anesthesia denial reasons is the first step to preventing them on surgical, OB, and radiology cases.
Start/stop time undocumented or not divided into 15-minute time units, dropping the time component of anesthesia reimbursement.
Capture documented anesthesia time in 15-minute units, reconciled to the anesthesia record on every claim.
AA vs. QK vs. QX/QZ applied incorrectly, triggering the wrong payment rate or denial for the provider arrangement.
Match the direction model (AA/QK/QX/QY/QZ/AD) to the actual CRNA arrangement on each claim.
P3-P6 modifiers not reported, losing qualifying-circumstance base units that commercial payers add for complex patients.
Apply the qualifying P modifier with supporting documentation where the patient’s status warrants added units.
Medical-direction cases exceeding the 4-procedure concurrency limit, invalidating the QK direction payment model.
Track concurrency in real time so direction arrangements stay within the 4-procedure medical-direction limit.
Identifying and plugging these common revenue leakage points can significantly improve your practice’s bottom line.
Minutes on the anesthesia record never converted to billable 15-minute time units.
QK/QX/QZ applied for the wrong CRNA arrangement, paying the wrong rate.
P3-P6 qualifying base units not reported on complex, high-acuity patients.
Direction of more than 4 concurrent procedures voids the QK payment model.
See how anesthesia-specific revenue cycle management transforms your practice’s financial performance.
A structured onboarding process designed to deliver measurable improvements within the first 90 days.
Review of anesthesia billing operations, time-unit capture, direction-modifier use, and revenue cycle baseline.
EMR and anesthesia-system integration, dedicated anesthesia billing team, and CRNA direction-model configuration.
Full billing with time-unit reconciliation, direction-modifier verification, and denial prevention protocols.
Performance review against baseline, workflow optimization, and documented revenue improvement.
How our anesthesia-specific approach compares to in-house billing and general medical billing companies.
| Capability | In-House Team | General Billing Co. | MedFactor Anesthesia |
|---|---|---|---|
| Time-unit reconciliation to anesthesia record | Inconsistent | ✕ | ✓ |
| Base-unit accuracy per anesthesia CPT | ✕ | ✕ | ✓ |
| CRNA direction modifiers (AA/QK/QX/QY/QZ) | Inconsistent | ✕ | ✓ |
| Physical status P3-P6 capture | ✕ | ✕ | ✓ |
| Concurrency-limit tracking | Manual | Partial | ✓ |
| OB conversion coding (01961 vs. 01967+01968) | Inconsistent | Partial | ✓ |
| Post-op pain management (01996) capture | Manual | Partial | ✓ |
| Time-unit capture rate reporting | ✕ | ✕ | ✓ |
| Dedicated anesthesia billing team | ✕ | ✕ | ✓ |
Our team combines deep anesthesiology billing expertise with the technology and processes to deliver consistent, measurable results for surgical, OB, and CRNA-directed practices.
Discover exactly where your anesthesia practice is losing revenue. Our no-obligation audit analyzes your time-unit capture, direction-modifier use, and P-status compliance.
Real results from anesthesiology practices that partnered with MedFactor for specialty revenue cycle management.
An ambulatory surgical center was rounding anesthesia time and dropping documented minutes on every case. MedFactor implemented anesthesia-record reconciliation to bill each documented 15-minute unit, recovering substantial surgical revenue in seven months.
A CRNA-staffed group was applying QZ for medically-directed cases and QX for independent ones, triggering payment-rate denials. MedFactor matched each claim’s direction modifier to the actual arrangement, recovering correct-direction reimbursement.
An OB anesthesia team was under-capturing cesarean base units and miscoding the 01968 conversion add-on. MedFactor corrected the 01961 vs. 01967+01968 scenario coding and added qualifying P-status units, lifting OB anesthesia revenue.
No matter where your anesthesiology practice operates, our team understands the payer landscape and regulatory requirements in your region.
Locality-adjusted Medicare conversion factors applied accurately across every region and practice setting.
Medical-direction and supervision rules mapped per commercial payer and state Medicaid.
Facility and professional anesthesia billing coordination across ASC and hospital-based cases.
State Medicaid OB anesthesia coverage and 01967/01968 conversion rules applied correctly.
Common questions from anesthesiology practices considering MedFactor’s specialty RCM services.
Anesthesia reimbursement equals (Base Units + Time Units) × the Conversion Factor. Time units are calculated from documented anesthesia time on the anesthesia record — the start time (induction / preparation) through the stop time (when the anesthesiologist is no longer in attendance). Medicare uses one time unit per 15 minutes, so documented minutes ÷ 15 = time units. Some commercial payers use a different increment. We reconcile every claim to the anesthesia record so each documented 15-minute block becomes a billable time unit instead of being rounded down or dropped.
AA means the anesthesiologist personally performed the service and is paid at 100% of the fee. QK means the anesthesiologist is medically directing 2-4 concurrent anesthesia procedures and is paid at 50%. QX means a CRNA is providing the service with medical direction by an anesthesiologist (the CRNA’s claim carries QX). QZ means a CRNA is providing the service without medical direction, paid to the CRNA independently. AD covers medical supervision of more than 4 concurrent cases and is capped at 3 base units. We match the modifier to the actual provider arrangement on each claim so the correct payment rate applies.
P1 through P6 are ASA physical-status modifiers reported on every anesthesia claim: P1 normal healthy patient, P2 mild systemic disease, P3 severe systemic disease, P4 severe systemic disease that is a constant threat to life, P5 moribund patient, and P6 brain-dead organ donor. Medicare does not pay additional units for P-status, but many commercial payers add qualifying base units for P3, P4, and P5 to reflect the added complexity. We capture the P modifier supported by the preoperative assessment on every case so those qualifying units are not lost on commercial claims.
Medical direction is the anesthesiologist directing 2, 3, or 4 concurrent anesthesia procedures (modifier QK). To qualify, the anesthesiologist must satisfy the seven TEFRA requirements: perform a preanesthesia exam, participate in induction, be present for the most demanding parts, provide postanesthesia care, remain immediately available, not perform other services, and document each. The anesthesiologist is paid 50% of the fee and the CRNA’s portion carries QX. Direction is limited to 4 concurrent procedures — beyond that, AD medical supervision applies (capped at 3 base units). We track concurrency in real time and configure the direction model to your actual CRNA arrangement.
Time units are calculated directly from documented anesthesia start and stop times on the anesthesia record. If the record is missing, incomplete, or doesn’t clearly show start (induction / preparation) and stop (anesthesiologist no longer in attendance) times, the payer cannot verify the time units and denies or downcodes the claim. Missing start/stop documentation is one of the most common anesthesia denials. We enforce anesthesia-record completeness before claim submission so every billable minute is backed by documentation the payer can validate.
We integrate with all major anesthesia information management systems (AIMS) and hospital EMRs including Epic, Cerner, Athenahealth, and anesthesia-specific documentation systems, plus practice management and billing platforms. Our team works with your anesthesia records — documented start/stop times, base-unit assignments, and direction arrangement — so procedure and time detail flows cleanly to correct claim submission, including the time units and direction modifiers that drive accurate anesthesia coding.
MedFactor applies the same code-level precision across the full practice spectrum. See how we bill these related specialties.
CPT®, ICD-10, HCPCS, and modifier codes referenced on this page reflect the current code sets and are subject to annual updates — always verify against the current-year fee schedule before submission. Base-unit values shown reflect the ASA Relative Value Guide / CMS anesthesia base-unit schedule; time-unit increments and physical-status add-on payments vary by payer. KPIs and case-study figures shown are representative benchmarks, not guarantees of individual practice results.
Your anesthesia practice deserves billing partners who know base + time-unit calculation, CRNA direction modifiers, and physical-status P1-P6 capture — and bill every unit correctly. Let MedFactor show you what specialty RCM can do.