Anaesthetic Item numbers and Anaesthesia  Explained

Anaesthetic item Numbers/ Anaesthesia codes and doctor billing for anaesthesia services can be a complicated, even daunting, task. Here is a summary to assist you with medicare coding.

Anaesthetic fees structure

The fee structure for Anaesthesia codes are divided into five main components:

1. Anaesthetic Consultation

2. Modifying units

3. Base Units

4. Time units

5.  Additional  procedure or specialised monitoring 

Anaesthetic Consultation

Item numbers for pre-anaesthesia consultations are both time based and complexity based. The medicare item numbers are charged in units of 15 minutes.

Anaesthetic Modifying units

Medicare Billing considers the complexity of the patient and circumstances of the situation.

Physical Status Modifier Codes takes into consideration the medical condition of the patient.


Other modifying codes take into consideration if the procedure is an emergency procedure and whether the procedure is carried out 'after-hours.'

Anaesthetic Time Billing Codes

The Anaesthetic bill coding for time is invoiced based on every 15 minutes for the first 2 hours of anaesthesia performed. Thereafter billing units are charged per 10 minutes of anaesthesia.

Anaesthetic Base Units

The Base unit medicare codes are allocated to each operation. The number of base units allocated to each operation are determined by degree of complexity of the operation based on the impact of that particular operation has on a patient's physiology.

Additional Anaesthetic Billing Codes

Finally additional units are added for specialised forms of monitoring for complex procedures and specialised procedures associated with the operation.


Specialised procedures item numbers are extensive. Examples are the administration of blood transfusions during the anaesthetic or administration of nerve blocks for pain relief post operatively.

Need more information regarding Anaesthesia Coding?

Why not get in contact with Fast Tracking Anaesthetic Billing Services. We can set you up in no time.
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