What is the ASA Classification?

The American Society of Anesthesiologists Classification, or ASA Classification, is a physical status classification that is used to assess and communicate a patient’s pre-anaesthetic co-morbidities. By assessing this, we can then gauge potential complications we may encounter peri-operatively and try to mitigate/minimise these.

It has been used for over 60 years, with the last update in 2014, as is a scoring system running from I to VI. The higher the score, the greater the risk in relation to anaesthesia.

Although the ASA Classification was initially developed for anaesthetic purposes, it is now more broadly used as a method to communicate the health of a patient. In dentistry, the ASA Classification is primarily used for assessing patients prior to sedation and general anaesthetic.

The ASA Classes

Below is a table that describes the classes with their definitions and examples as provided by the American Society of Anesthesiologists. A patient just needs one of the conditions listed to put them in to that category and we take the highest class for that patient.ASA Classification Explained

If we consider the dental implications of these classes:

  • Generally, ASA I and II patients are safe to treat in general practice with none or minor modifications.
  • ASA III and IV patients may require more substantial changes to their management, and potentially referral to a hospital-setting. Elective treatment should be avoided on ASA IV patients.

Examples of the ASA Classification

Example 1

A 46 year old male attends for a filling. They have a medical background of Type 2 diabetes and asthma. They smoke around 5 cigarettes/day. Their HbA1c is 5% and they rarely require their salbutamol inhaler. 

In this example, we are told the patient is a type 2 diabetic. The reading we are provided is a HbA1c of 5%. Ideally, for well-controlled diabetes, the HbA1c should be below 7% – therefore this patient is well-controlled. Additionally, the patient is an asthmatic but they rarely use their inhaler. This would suggest well-controlled asthma. Finally, the patient is a smoker. All of these factors would mean the patient is ASA II.

Example 2

A 47 year old female attends for a routine checkup. She had a medical background of Type 2 diabetes, with a HbA1c of 6%. She tells you she has a history of heart problems and she had a heart attack around 2 months ago. Her BMI is 33. 

As discussed above, this patient’s diabetes would be classed as well-controlled given the HbA1c reading. Her BMI is 33, which would also put her in an ASA 2 group like the diabetes. However, the patient has had an MI in the last 3 months and therefore, they would fall in to an ASA IV group. Elective treatment should be avoided.

ASA Classification Summary

  • The ASA Classification is a physical status classification used to determine a patient’s risk with anaesthesia.
  • The classification runs from ASA I to ASA VI. The higher the number, the greater the risk.

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BDS (Hons.) MFDS RCPS (Glasg.) Cert Med Ed FHEA - Currently working as a Speciality Doctor in OMFS and as an Associate Dentist


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