AJ Modifier: Billing and Coding for Licensed Clinical Social Workers

The AJ Modifier, like some of the HCPCS H modifiers, is used in coding claims. These modifiers differ from diagnosis or CPT procedure codes, and are used to describe a different aspect of the claim.

One similar example is the HO modifier which is sometimes required by insurance companies and shows the degree level (Master’s level in this case)

AJ Modifier Description

The AJ signifies that the provider is a LCSW or Licensed Clinical Social Worker. Not sure if you need to file with AJ on your claims? This is where a billing service such as TheraThink can help to determine by calling the insurance company and getting the correct coding standard.

There are a number of other similar modifiers including other A modifiers and H ones. For instance, AF indicates a specialty physician and AH a clinical psychologist.  (Source)

AJ vs. HO

HO signifies a masters degree. Since being a LCSW requires a master’s degree, HO and AJ could in theory both apply. So should you use both?

There is no standard and this depends on the insurance company. Medicaid in Vermont may require an AJ modifier whereas UHC Medicaid in Wisconsin may require HO if both apply.

Is This a Universal Insurance Requirement?

No, most insurance companies including private insurance and Medicare do not ask that social workers claims be filed with the AJ modifier. CMS stated in 2013 that this is not a modifier that is required for most claims.

Billing AJ Modifier

AJ & Medicaid. Filing Guidelines

The vast majority of companies that require AJ are Medicaid companies. Even though the majority of Medicaid companies do not require AJ, or the applicable equivalent, some still do.

We recommend researching this and calling the EDI department of the Medicaid department if you take this type of insurance. A service like TheraThink can call ahead to make sure it is being properly billed.

What CPT Code Do I Use With AJ?

This is billed with standard mental health CPT codes like 90791, 90834, or 90837.

Unfortunately even though insurance companies follow fee schedules for CPT codes, the modifier may reduce the reimbursement of the claims.

We have commonly see reimbursement for providers that are required to file with AJ come in at ~75% of the full reimbursement rate that a Psychiatrist may receive.

Therefore if multiple modifiers apply we recommend filing with the highest credentialed modifier applicable.

Modifier AJ CPT codes:

  • 90801 – 90828
  • 90841 – 90857
  • 90875 – 90876

Modifier AJ HCPCS codes:

  • G0071
  • G0073
  • G0075
  • G0077
  • G0079
  • G0081
  • G0083
  • G0085
  • G0087
  • G0089
  • G0091
  • G0093
  • H5010 – H5030


AJ Modifier Useage. How Do I Bill AJ on a CMS 1500 Form?

The AJ modifier should be used under the 24d field on the CMS 1500, with the CPT code in 24c.

AJ Modifier

1 Comment

  1. Christine R January 10, 2021 at 11:28 am #

    This was very helpful, thank you!


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