CurrentMolina HealthcarePolicy N/A

Add-on code billing and reimbursement guidance

Defines Molina Healthcare's reimbursement policy and billing guidance for CPT add-on codes and related coding/billing practices; affects providers submitting claims to Molina (state Medicaid/Marketplace and other Molina lines).

Policy Summary

PayerMolina Healthcare

PolicyAdd-on code billing and reimbursement guidance

Policy CodePolicy N/A

Change TypeUpdated examples and template

Effective DateN/A

Next Review DateN/A

Key ActionWhen billing add-on codes, ensure the primary procedure is billed by a provider of the same specialty in the same group practice.

SourceLink

POLICY UPDATE CHANGES

Updated Examples, Updated Template and Verified Links.

Verified Links Updated Template.

Updated examples.

Updated Template Format.

4document revision dates listed

2example add-on code scenarios provided

1policy purpose statement

Add-on Code Billing Criteria

Add-on code billing criteria

Covered when ALL of the following conditions are met:

Policy Summary

PayerMolina Healthcare

PolicyAdd-on code billing and reimbursement guidance

Policy CodePolicy N/A

Change TypeUpdated examples and template

Effective DateN/A

Next Review DateN/A

Key ActionWhen billing add-on codes, ensure the primary procedure is billed by a provider of the same specialty in the same group practice.

SourceLink

On This Page

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Add-on codes are identified by CMS as 'ZZZ' in the Medicare PFS database or by '+' in the CPT manual.

An add-on code generally requires a separately reported primary procedure; exceptions below describe the limited circumstances when an add-on may be billed without the primary procedure.

When billing an add-on code without the primary procedure, the primary procedure must be billed by a provider of the same specialty in the same group practice.

Examples (one of):

CPT 58110 — Endometrial sampling (biopsy). Primary procedures include 57420, 57421, 57452, 57461.
CPT 88341 — Immunohistochemistry additional antibody stain. Primary procedure: 88342.
CPT 99292 — Critical care each additional 30 minutes. For the same date of service, one physician of the same specialty in the group may report CPT 99291 (with or without 99292); other physicians in the same group may report 99292 for their critical care services.
CPT 01968 — Anesthesia for cesarean delivery following neuraxial labor analgesia/anesthesia. For Medicaid and Marketplace services, one anesthesia provider may report 01967 and another anesthesia provider in the same group practice may report 01968.

Listing of a code in this policy does not guarantee coverage; coverage is determined by the member's benefit document, applicable laws, and state/federal guidance.

Molina will monitor compliance with billing of add-on codes and may take corrective action for noncompliance with coding and billing standards.

Example Add-on Codes & Identification

Example add-on codesCPT

58110	Endometrial sampling (biopsy) with or without endocervical sampling (biopsy), without cervical dilation, any method (separate procedure)
88341	Immunohistochemistry or immunocytochemistry, per specimen; each additional single antibody stain procedure
99292	Critical care, evaluation and management of the critically ill or critically injured patient; each additional 30 minutes
01968	Anesthesia for cesarean delivery following neuraxial labor analgesia/anesthesia

CMS add-on identification

Identification methodsAdd-on codes are identified by 'ZZZ' in the Medicare Physician Fee Schedule (global surgery period) database or by the '+' symbol in the CPT Manual.

Data source (Medicare PFS)'ZZZ' appears in the global surgery period column of the Medicare Physician Fee Schedule Database to denote add-on codes.

Data source (CPT Manual)The '+' symbol in the CPT Manual indicates add-on codes per CMS acknowledgement.

Billing and Monitoring Requirements for Add-on Codes

Billing Rule

Add-on code billing and monitoring requirement

When billing add-on codes under the two specified circumstances, the primary procedure must be billed by a provider of the same specialty in the same group practice; Molina will monitor compliance and take corrective action for coding/billing noncompliance.

Example 1: For CPT 99292, on the same date of service only one physician of the same specialty in the group may report CPT 99291 (with or without 99292); other physician(s) in the group must report their critical care services with CPT 99292.
Example 2: For Medicaid and Marketplace services, one anesthesia provider may report CPT 01967 and another anesthesia provider in the same group practice may report CPT 01968.

Acronym Definitions

CMS — Definitions & policy note

Acronym CMSCenter for Medicare and Medicaid.

Acronym CPTCurrent Procedural Terminology.

Policy monitoringMolina Healthcare will monitor compliance with this policy and take corrective action as necessary to ensure adherence to coding and billing standards.

CPT — Definitions & usage

CPT definitionCurrent Procedural Terminology.

Use in policyCPT codes (including add-on codes identified by '+') are used to define procedures and billing rules in this policy.

Coverage disclaimerListing of codes does not guarantee coverage; benefit documents and applicable laws determine coverage.