Proactively manage genetic test spend with DEX Z-Codes®

Genetic testing utilization continues to grow, but reimbursement policies and enforcement are struggling to keep pace. More than 175,000 genetic tests were available in 2025, but only 500 CPT® codes were used to identify them — and the codes that do exist rarely describe the specific test performed.

This gap in unique test identification can make genetic testing reimbursement challenging for health plans, but it’s only part of the problem. Effectively managing genetic testing spend requires unique test identification along with a comprehensive approach to coverage, coding and payment policy enforcement.

Read on to learn how the DEX® Diagnostics Exchange helps improve quality for members and physicians by not only creating a unique identifier but validating that genetic tests truly meet their stated clinical purpose.

What are Z-Codes?

A Z-Code is a unique identifier assigned to an individual genetic test through the DEX® Diagnostics Exchange, managed by Palmetto GBA®. Unlike standard procedure codes, a Z-Code links a claim to specific details about the test, including the performing laboratory, testing methodology and clinical purpose. This additional level of specificity allows health plans to more accurately identify and reimburse genetic tests at the individual test level.

In addition to helping identify unique genetic tests, the DEX Diagnostics Exchange also helps confirm the overall quality of a genetic test. When a lab registers their test with DEX, tests undergo a rigorous technical assessment to evaluate many factors, including:

• Is a specific assay analytically sound?
• Does the test accurately and reliably detect what it claims to detect?
• Is it clinically valid?
• Is the detected biomarker meaningfully associated with the disease or condition of the patient and clinically useful?
• Does the test result change patient management and improve clinical decision making?

Results of the assessment ultimately determine coverage, pricing and coding for each unique test.

Is Z-Code usage expanding beyond Medicare claims?

Yes. For more than 15 years, the Centers for Medicare & Medicaid Services (CMS) has used Z-Codes through the MoIDX® Program to identify unique molecular diagnostic tests and support coverage and reimbursement decisions.

Today, the use of Z-Codes has expanded beyond Medicare to include commercial health plans and managed Medicaid through the DEX® Registry. Growing industry support — including a 2026 recommendation from the Blue Cross Blue Shield Association that CMS consider nationalizing the MolDX® program — highlights the increasing need for standardized oversight of molecular and genetic testing.

How can Z-Codes help manage genetic test spend?

DEX Z-Codes® provide the test-level visibility needed to more effectively manage genetic testing spend. By identifying the exact genetic test billed, health plans can move beyond broad procedure codes and apply coverage, coding and reimbursement policies at the individual test level.

With Z-Codes, health plans can:

• Apply coverage and reimbursement policies to specific genetic tests rather than relying solely on CPT, PLA or HCPCS codes
• Prevent payment for non-covered, duplicative or low-value tests
• Apply payment policies consistently across all lines of business
• Automate policy enforcement at the claim line, reducing the need for manual review

This level of precision helps health plans improve oversight, reduce inappropriate utilization and better manage genetic testing costs.

Do Z-Codes impact the prior authorization process?

Prior authorization has long served as the primary tool for managing genetic testing, but it is labor-intensive, creates provider abrasion and delays care. Much of that burden exists because traditional coding cannot reliably identify which test was actually performed. DEX Z-Codes address this root cause by uniquely identifying each discrete, vetted test at the point of the claim.

By closing the information gap that prior authorization was designed to fill, Z-Codes allow health plans to automate or shift review downstream without sacrificing control. Key benefits include:

• Enabling automation strategies that reduce or shift prior authorization to post-service verification
• Establishing a one-to-one relationship between the test, CPT code, diagnosis and lab to support automated policy enforcement
• Carrying built-in quality vetting through completed technical assessments, reducing the need for manual clinical review
• Supporting appropriate test selection at the point of ordering rather than through an upfront authorization gate

By providing test-level identification and enabling automated policy enforcement, Z-Codes help health plans reduce prior authorization burden while preserving the oversight, consistency and defensibility that manual review was intended to provide.