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Humana implements pass-through billing code editing that affects modifier 90

What is pass-through billing?

Pass-through billing occurs when an ordering health care provider requests and bills for a service, but the service is not performed by the ordering health care provider or individuals under the ordering health care provider’s direct employment.

What is CPT modifier 90?

The CPT 2016 Professional Edition describes modifier 90 as follows:

Reference (Outside) laboratory: When laboratory procedures are performed by a party other than the treating or reporting physician, or other qualified health care professional, the procedure may be identified by adding the modifier 90 to the usual procedure number.

What is changing?

We recently provided notice that we will introduce claim code editing to prevent reimbursement of charges submitted by a professional practitioner for a laboratory procedure performed by an outside laboratory.

We will continue to allow independent laboratories to submit modifier 90.

What plans are affected, and when will this change be effective?

This change affects commercial, self-funded and Medicare Advantage (MA) plans and is effective April 18, 2016. This change was included in the Jan. 16, 2016, claim processing updates. You can view the notification here.

Humana encourages professional practitioners to refer to participating laboratories, such as LabCorp and Quest Diagnostics. Both LabCorp and Quest Diagnostics offer extensive test options. The outside laboratory may then bill for physician-referred and nonphysician-practitioner-referred services.

Independent laboratories need to use modifier 90 to identify laboratory services they refer to another laboratory.

Additional information about this change and other code-editing changes are available through the code-editing questions tool. To access the code-editing questions tool, you must be registered on Humana's website or the multipayer Availity Web Portal.

To submit a code-editing question on

  1. If you are not registered for the secure portal, go to and choose “Sign in or Register” or contact your primary access administrator.
  2. Once logged in, click the “Claims Tools” tab at the top of the page.
  3. Select “Code Edit Questions” to access the tool.

To submit a code-editing question on Availity:

  1. If you are not registered for Availity’s secure portal, go to and select “GET STARTED” to sign up.
  2. Once logged in, select “Claims Management” from the links on the left.
  3. Select “Research Procedure Code Edits” to access the tool.