Anesthesia Billing Services

Anesthesia billing does not work like most other specialties. Payment is built from units rather than a flat fee per procedure. A claim combines base units (a value set for the surgical procedure), time units (how long anesthesia care lasted), and sometimes modifying units, then multiplies the total by a conversion factor set by the payer.

Staffing adds another layer. Anesthesiologists, CRNAs (certified registered nurse anesthetists), and anesthesiologist assistants may work alone, together, or under medical direction. Each model uses its own modifiers and payment rules. Westmont connects anesthesia groups, CRNA practices, and facilities with vetted billing experts who know how to capture time, units, and staffing details correctly.

Who this is for

• Anesthesiology groups of any size
• Independent CRNA practices
• Anesthesia care teams with medical direction or supervision
• Anesthesia groups covering hospitals, surgery centers, and offices
• Obstetric anesthesia programs
• Pain and regional anesthesia services in a facility setting

What gets billed

• General anesthesia for surgical and diagnostic procedures
• Monitored anesthesia care (MAC), where an anesthesia professional monitors a patient during a procedure
• Regional anesthesia and nerve blocks
• Labor epidural and cesarean delivery anesthesia
• Endoscopy and colonoscopy anesthesia
• Post-operative pain blocks when separately reportable
• Daily management of continuous epidural or similar pain therapy
• Physical status modifiers (P1 to P6) that describe patient health
• Qualifying circumstances such as extreme age or emergency conditions
• Medical direction and supervision of CRNAs and other staff

Commonly billed codes

Code	Type	What it covers
00840	CPT	Anesthesia for lower abdominal surgery inside the abdominal cavity
00811	CPT	Anesthesia for lower intestinal endoscopy, not otherwise specified (screening colonoscopy has its own code)
01402	CPT	Anesthesia for open or scope-assisted knee joint surgery
01961	CPT	Anesthesia for cesarean delivery
01967	CPT	Anesthesia for planned vaginal delivery with neuraxial pain relief
01996	CPT	Daily management of continuous epidural or spinal drug therapy
64415	CPT	Nerve block injection of the brachial plexus, single shot
99100	CPT	Qualifying circumstance add-on for patients at extreme ages
99140	CPT	Qualifying circumstance add-on for emergency conditions
AA	Modifier	Anesthesiologist personally performed the anesthesia
QK	Modifier	Anesthesiologist medically directing two to four concurrent cases
QY	Modifier	Anesthesiologist medically directing one CRNA
QX	Modifier	CRNA service with medical direction by a physician
QZ	Modifier	CRNA service without medical direction
P1 to P6	Modifier	Patient physical status levels, from healthy to declared brain-dead

Note

Codes are examples for orientation, not a complete list, and do not guarantee coverage or payment. Always check current code sets and payer policy.

Billing challenges in anesthesia

• Time reporting. Anesthesia time runs from when the provider begins preparing the patient to when the provider is no longer in personal attendance. Medicare generally converts minutes to units in 15-minute blocks, and some payers use other increments. Billers capture exact start and stop times and apply each payer's rule.
• Base units and conversion factors. Base units come from the anesthesia code, and conversion factors differ by payer and region. Billers keep payer fee tables current and check that expected payment matches what was paid.
• Medical direction versus supervision. Medicare has set conditions for medical direction, including limits on how many concurrent cases a physician may direct. Billers verify the care model and match modifiers such as QK, QY, QX, and AD to the record. Check current CMS guidance.
• CRNA billing models. CRNAs may bill on their own or through a group, with or without direction. Payment rules vary by payer and state. Billers confirm enrollment, reassignment, and modifier use for each provider.
• Physical status and qualifying circumstances. Many payers pay extra units only for certain physical status levels or add-ons. Billers review documentation so reported levels are supported.
• Surgical code mismatches. Anesthesia must be reported with the anesthesia code tied to the procedure performed. If the surgery is changed or coded differently, anesthesia claims can deny. Billers cross-check operative reports.
• Nerve blocks and pain procedures. A block used for surgical anesthesia is treated differently from one used for post-operative pain. Billers review who ordered the block and document the reason.
• Missing records. Anesthesia records are often paper or spread across systems. Billers set up a steady feed of anesthesia records and chart review for missing time or signatures.

How Westmont can help

• Match your group with vetted billing experts experienced in anesthesia and CRNA billing
• Support end-to-end revenue cycle work, from case capture to payment posting
• Help with denial management, including time, modifier, and medical direction denials
• Assist with credentialing and payer enrollment for anesthesiologists and CRNAs
• Review contracts, conversion factors, and underpayments by payer

Frequently asked questions

How is anesthesia billed differently from other services?

Anesthesia claims are calculated from base units, time units, and any modifying units, then multiplied by a payer's conversion factor. Most specialties are paid by procedure or visit. Because time and staffing affect payment, accurate start and stop times and correct modifiers are required on every claim.

What are base units in anesthesia billing?

Base units are a set value assigned to each anesthesia code to reflect the work and risk of the related procedure. They are added to time units to determine total units. Values come from published anesthesia crosswalks. Payers may use different versions, so check the schedule each payer follows.

What do QK, QY, QX, QZ, and AD mean?

QK is for a physician directing two to four concurrent cases. QY is for directing one CRNA. QX is for the CRNA in a directed case. QZ is for a CRNA working without direction. AD is for supervision of more than four cases. Medicare payment varies by modifier, so confirm with current CMS and payer policy.

How do you bill when a CRNA and an anesthesiologist share a case?

It depends on the care model. In a directed case, each provider bills with the matching modifier, and Medicare generally pays each provider a reduced share of the allowed amount. In other models, one provider may bill alone. Payers differ, so verify rules and documentation before billing.

Can anesthesia providers bill for nerve blocks?

Sometimes. If a block is part of the surgical anesthesia plan, it is usually not paid separately. If the surgeon requests it for post-operative pain and documentation supports it, many payers allow separate billing. Policies vary, so check each payer.

Related billing services

• ASC Billing
• General Surgery Billing
• Surgical Hospital Billing
• Pain Management Billing
• OB/GYN Billing
• Orthopedic Billing