CPT Category III Codes
Temporary CPT codes (xxxxT) for emerging technology, services, and procedures.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Coding
- Primary sources
- 1
- Workspace handoff
- denial workbench →
Where this comes up
Coders meet this term inside the chart at the moment of code selection — picking the E/M level, attaching the right modifier, defending the procedure code against an NCCI edit, or answering an auditor who pulled the encounter for a payer-initiated review.
Full definition
What it is in practice
The AMA assigns Category III codes when a service is not yet established enough for Category I. Codes sunset after 5 years unless promoted to Category I. Payer coverage is variable.
How it shows up in your practice
When billing Category III codes, expect denials and prepare medical-necessity documentation. Some payers process them only via prior auth.
Sources
- AMA — CPThttps://www.ama-assn.org/practice-management/cpt
Defend Category III denials in the Denial Workbench
Open denial workbench →Related terms
- BillingCPT (Current Procedural Terminology)The AMA-maintained code set that describes medical, surgical, and diagnostic services for billing.
- CodingMedical NecessityThe standard requiring that services be reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member.
- PayerPrior AuthorizationPayer requirement that the practice obtain approval before delivering certain services, procedures, or drugs.
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Related across the archive
- GlossaryCPT (Current Procedural Terminology)The AMA-maintained code set that describes medical, surgical, and diagnostic services for billing.
- GlossaryMedical NecessityThe standard requiring that services be reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member.
- GlossaryPrior AuthorizationPayer requirement that the practice obtain approval before delivering certain services, procedures, or drugs.
- GlossaryHCPCS Level IIThe CMS-maintained code set covering products, supplies, and services not included in CPT — primarily durable medical equipment, drugs, and Medicare-specific services.
- GlossaryModifier 25CPT modifier indicating that a significant, separately identifiable E/M service was performed by the same provider on the same day as another procedure or service.
- GlossaryModifier General ReferenceCatch-all reference for the wide CPT and HCPCS modifier set used in physician and outpatient billing.
- Billing99214 vs 99215: When to Bill Each CodeLearn the difference between 99214 and 99215: when each applies, what documentation you need, and the $40/visit revenue impact.
- BillingThe ICD-10 Codes That Get Primary Care Claims Denied (and How to Pick the Right One)I10 vs I11, E11.9 vs E11.40, Z00.00 vs Z00.01. The diagnosis coding mistakes that cause denials and how to fix them.
This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.