Pass-Through Billing Generally Not Permitted

Pass-through billing occurs when an ordering physician requests a service and bills insurance for it but does not perform the service, nor does anyone under the physician’s direct employ. Insurance companies generally forbid this practice.

Say, for example, you draw blood and send the specimen for testing to an outside lab that sends you the results. The lab bills you for its work, then you bill the patient’s insurance plan for that expense, or you bill the patient separately for the lab expense, in addition to filing a claim with the patient’s insurance plan for the other components of your service. That is pass-through billing. The lab, not the physician, should bill the payer for its work.

Here are policies from some of Texas’ top payers. 

From Aetna’s secure provider website: Laboratory, Pathology and Blood Procedures Payment Policy

We pay facilities for laboratory tests only when the member is a registered inpatient or outpatient of the facility. We consider the patient as an outpatient of a facility when one of the following occurs: 

  • Specimen collection occurs when he or she is present in the facility*, or
  • The patient receives other outpatient services at the facility on the same day the specimen is collected*. 

We do not pay for pass-through billing of laboratory tests. … Providers should only bill us for lab services they perform. Otherwise, we require a claim from the laboratory that actually performed the test. 

* This does not apply to molecular pathology lab tests.


The performing physician, professional provider, facility or ancillary provider is required to bill for the services they render unless otherwise approved by Blue Cross and Blue Shield of Texas (BCBSTX).

BCBSTX does not consider the following scenarios to be pass-through billing:

  • The service of the performing physician, professional provider, facility or ancillary provider is performed at the place of service of the ordering provider and is billed by the ordering physician or professional provider, or
  • The service is provided by an employee of a physician, professional provider, facility or ancillary provider … and the service is billed by the ordering physician or professional provider.
  • The service is billed by the ordering physician or professional provider.

Further, BCBSTX says the supervising physicians should use the correct modifiers when billing for services rendered by a physician assistant (PA), advanced practice nurse (APN), registered nurse first assistant (RNFA), or licensed surgical assistant (LSA):

Append the AS modifier for PAs, APNs, certified RNFAs, and LSAs when:

  • They assist surgeons as a surgical assistant;
  • The supervising physician bills on their behalf including their national provider identification (NPI) number; and
  • They submit claims with their own NPI.

Append the SA modifier:

  • To supervising physician claim submissions when billing on behalf of PAs, APNs, or certified RNFAs for nonsurgical services; and
  • When these professionals bill with their own NPI number for assisting with other nonsurgical procedures.

Claims will be processed based on the individual’s contracting status.

 From Cigna’s secure provider website: Laboratory Services Reimbursement Policy

Cigna does not reimburse modifier 90 – Reference (outside) laboratory. Modifier 90 indicates pass through billing for a service that was not performed by the billing provider. Cigna will only reimburse providers for procedures that are performed by the same provider

 From Humana’s provider manual:

Humana prohibits pass-through billing. … Pass-through billing services will not be eligible for reimbursement from Humana, and the provider shall not bill, charge, seek payment or have any recourse against Humana or members for any amounts related to the pass-through billing provision. See the providers’ section of for Humana’s claims payment policy on pass-through billing.

 From UnitedHealthcare’s administrative guide:

You may only bill for services that you or your staff perform. You may not bill on behalf of another provider who actually performed the services.

Pass-through billing is not permitted and may not be billed to our members.

We only reimburse for laboratory services that you are certified to perform through the federal Clinical Laboratory Improvement Amendments [CLIA].You must not bill our members for any laboratory services and respective procedure codes if you don’t have the applicable CLIA certification.

Have a coding or billing question? Email your question to TMA’s reimbursement specialists at reimbursementservices[at]texmed[dot]org, or call (800) 880-7955. 

Last Updated On

September 14, 2022

Originally Published On

February 07, 2017