Learn more about the three main factors that need to be considered in anesthesia medical billing and coding.

1. 3
Crucial Factors to
Consider When Coding for
General Anesthesia Services

2. Anesthesia charges are calculated on the basis of factors such as the complexity of
the procedure, its duration and modifying factors such as the patient’s health and
where the service is provided. In Anesthesia medical billing, you must take into
consideration the base value units, time units and the modifying units. The total
anesthesia charge is calculated by multiplying the total number of units (base units
+ time units + modifying units) with the conversion factor (dollar amounts specified
for a particular geographic area).
Base Value Units
The American Society of Anesthesiologists (ASA) Relative Value Guide assigns a
basic value to the anesthetic management of surgical procedures. The base unit
indicates how hard the anesthesia procedure is to perform and how much skill is
required. The more difficult the procedure, the higher the base units. If multiple
surgical procedures are performed under a single anesthetic, the value of the
procedure with the highest number of base units should be reported as the base
value. The base value includes all usual anesthesia services such as usual pre- and
post-operative visits, the interpretation of noninvasive monitoring (for instance ECG,
oximetry, capnography) and administration of fluids and/or blood products incident
to anesthesia care.
Time Units
The time taken to provide anesthesia (anesthesia time) is expressed as ‘Time Units’.
Anesthesia time starts when the anesthesia provider starts to prepare the relevant
patient for anesthesia induction (typically in the case of intravenous access) and
stops when that patient is no longer provided personal attendance (the patient is
placed safely under postoperative supervision). Though the basic ‘Time Units is
normally considered to be 15 minutes, the definition may vary according to the
insurance carrier (for instance, some may consider 10 minutes as basic ‘Time Unit’).
It is best to clarify with the incurrence carriers how they define the time units and
how they prefer them to be reported.

3. The HIPAA Electronic Transaction Standard 5010 does not accept units, but requires
total anesthesia time to be reported on the claim form under the column ‘Units’. In
the CMS 1500 form, the anesthesia units can be reported in the field under 24G ‘Day
or Units’ box. Normally, anesthesia services must be reported in minutes in this
form. Units may be reported only if the code description of relevant anesthesia
service includes a time period.
Modifying Units
The modifying unit indicates the special conditions that may affect the anesthesia
procedure, or provides additional information that is not specified by the procedure
code. Different types of modifying units for general anesthesia services are:
HCPCS Level II Modifiers
Sometimes, the operating surgeon may request general anesthesia services and a
CRNA (Certified Registered Nurse Anesthetist) or a physician other than the surgeon
to provide the services; or sometimes the operating surgeon may perform the
sedation procedure as part of a surgical or diagnostic procedure. In Medicare, the
payment for general anesthesia administered or supervised by the operating surgeon
is bundled.
HCPCS Level II modifiers are used to indicate whether anesthesia services are
performed by anesthesiologists or CNRA and other additional information about the
services (medical direction and medical supervision).
Modifiers Used By Anesthesiologists

AA: Anesthesia services performed personally by anesthesiologist

AD: Medical supervision by a physician (anesthesiologist); more than four
concurrent anesthesia procedures

QK: Medical direction (supervision) of two, three or four concurrent
anesthesia procedures

QY: Anesthesiologist medically directs one CRNA

4. Modifiers Used By Certified Registered Nurse Anesthetists (CRNAs)

QX: CRNA service with medical direction (supervision) by a physician

QZ: CRNA service without medical direction (supervision) by a physician
Physical Status Modifiers
These modifiers are used to specify the health conditions of the patient at the time of
providing anesthesia or simply the complex levels of anesthesia services. This
modifier should be reported only with the CPT codes that report anesthesia services
(00100-01999), and should be placed after the HCPCS Level II modifiers (for
example, 25270-AA-P2).

P1: Normal healthy patient (0 value unit)

P2: Patient with mild systemic disease (1 value unit)

P3: Patient with severe systemic disease (2 value units)

P4: Patient with severe systemic disease that is a constant threat to life (3
value units)

P5: Moribund patient, not expected to survive with-out the operation (0 value
unit)

P6: Declared brain-dead patient whose organs are being removed for donor
purposes (0 value unit)
Qualifying Circumstances
Codes denoting qualifying circumstances describe the anesthesia services provided
under difficult or unusual circumstances. Anesthesia time and modifiers are not
required along with qualifying circumstances codes. Reporting these in addition to
the anesthesia code, may qualify for additional reimbursement (depending on the
carrier). They may be reported along with more than one CPT code.

+99100: Anesthesia for patient of extreme age, under one year or over 70
(1 value unit)

+99116: Anesthesia complicated by utilization of total body hypothermia (5
value units, additional units are permitted in rare cases)

5. 
+99135: Anesthesia complicated by utilization of controlled hypotension (5
value units)

+99140: Anesthesia complicated by emergency conditions (2 value units)
An emergency exists when there is a treatment delay which would lead to
considerable increase in the threat to a patient’s life or body part.
Specialized Monitoring and Other Miscellaneous Procedures
Though used to describe additional procedures/services, these are not technically
modifiers and are used along with anesthesia codes in special cases. No anesthesia
time and modifiers are required or needed to be reported with these codes.

36000: Induction of needle or intracatheter, vein (5 Value Units)

36010: Introduction of catheter, superior or inferior vena cava (5 Value
Units)

36014: Pulmonary artery line (7 Value Units)

36400: Venipuncture, under age 3 years, femoral, jugular or sagittal sinus (2
Value Units)

36410: Venipuncture, over age 3 years or adult, necessitating physician's
skill (1 Value Unit)

36420: Venipuncture, cutdown, under age 1 year (5 Value Units)

36425: Venipuncture, cutdown, age 1 or over (3 Value Units)

36555: Insertion of non-tunneled centrally inserted central venous catheter;
under 5 years of age (5 Value Units)

36556: Insertion of non-tunneled centrally inserted central venous catheter;
age 5 years or older (4 Value Units)

36600: Arterial puncture, withdrawal of blood for diagnosis (1 Value Unit)

36620: Insertion of an arterial line; percutaneous (3 Value Units)

36625: Insertion of an arterial line; cutdown (5 Value Units)

36660: Catheterization, umbilical artery, newborn for diagnosis or therapy (5
Value Units)

93312:
Echocardiography,
transesophageal,
real-time
with
image
documentation (2D) (with or without M-mode recording); including probe
placement, image acquisition, interpretation and report (6 Value Units)

93313:
Echocardiography,
transesophageal,
real
time
with
image
documentation; placement of transesophageal probe only (2 Value Units)

6. 
93314:
Echocardiography,
transesophageal,
real-time
with
image
documentation (2D) (with or without M-mode recording); image acquisition,
interpretation and report only (4 Value Units)

93315: Transesophageal echocardiography for congenital cardiac anomalies;
including probe placement, image acquisition, interpretation and report (8
Value Units)

93316: Transesophageal echocardiography for congenital cardiac anomalies;
placement of transesophageal probe only (3 Value Units)

93317: Transesophageal echocardiography for congenital cardiac anomalies;
image acquisition, interpretation and report only (5 Value Units)

93318: Echocardiography, transesophageal (TEE) for monitoring purposes,
including probe placement, real time 2-dimensional image acquisition and
interpretation leading to ongoing (continuous) assessment of (dynamically
changing) cardiac pumping function and to therapeutic measures on an
immediate time basis (6 Value Units)

93503: Insertion and placement of flow directed catheter (e.g. Swan-Ganz)
(10 Value Units)
The allowable charges for general anesthesia are calculated by the formula
(Anesthesia Base Units + Anesthesia Time Units + Physical Status Modifier +
Qualifying Circumstances + Specialized Monitoring) x Anesthesia Conversion Factor.
Anesthesiology medical coding and billing is distinct from that of other specialties
that focus on fee-for-service payment. Reliable and dedicated support from a
professional medical billing and coding company can ensure accurate general
anesthesia coding and billing.