CPT — Current Procedural Terminology

Before you start: this page assumes you already know what medical coding is and why it exists — if "ICD-10-CM," "claim," or "payer" are new terms to you, do Medical Coding Overview first (it covers the billing pipeline these codes feed into). Basic medical terminology (prefixes, roots, suffixes) also helps for reading procedure names, though it isn't strictly required to follow this page.

When a patient sees a doctor, the provider doesn't just get paid automatically — they submit a claim: a formal, itemized bill sent to whoever is going to pay for the visit. The payer is whoever that is — an insurance company, Medicare, Medicaid, or (rarely) the patient directly. A payer won't just pay a claim on trust; it needs to see exactly what was done, coded in a standard way it can look up and price. That's what CPT codes are: a standardized code set describing medical services and procedures, so every claim says precisely what happened in a language every payer already understands.

CPT codes are used to report medical, surgical, and diagnostic procedures performed by physicians and other healthcare providers. Maintained by the American Medical Association (AMA) and updated annually.

Analogy — If ICD-10-CM (a separate code set, covered in its own section) is the "why" on a claim, CPT is the itemized receipt of "what was actually done." Think of a car repair invoice: the diagnosis is "why you came in" ("check engine light"), and the line items — "replaced spark plugs, $80; diagnostic scan, $40" — are the CPT equivalent. A payer won't reimburse (pay out) a claim that only says why the patient came in without also itemizing exactly what service was performed, any more than a garage could bill you without listing the actual repairs.

ICD-10-CM: "why"                CPT: "what was done"
I10 (Essential hypertension)  + 99213 (established patient office visit)
        "diagnosis"                    "the billable service"

What is CPT?

CPT (Current Procedural Terminology) is a standardized code set that describes medical services and procedures. Every billable service a provider performs has a CPT code — from a routine office visit to complex surgery to laboratory tests.

Key facts:

•Published and maintained by the AMA

•Updated annually — new edition effective January 1st

•Required for all outpatient claims to payers (the insurer or program being billed)

•5-digit numeric codes (some alphanumeric in Category II/III)

•Different from ICD-10-CM (diagnoses) — CPT is WHAT was done, ICD-10-CM is WHY

CPT Code Categories

Category I — Main codes describing procedures and services

Category II — Supplemental tracking codes (performance measures, optional, end in F)

Category III — Temporary codes for new/experimental technologies (end in T)

Code Structure — Category I

CPT codes are grouped into 6 sections:

99202-99499    Evaluation and Management (E/M)
00100-01999    Anesthesia
10004-69990    Surgery
70010-79999    Radiology
80047-89398    Pathology and Laboratory
90281-99199    Medicine

Evaluation & Management (E/M) — Most Used

E/M codes represent office visits, hospital visits, consultations. They are the most commonly used and most audited CPT codes.

Office/Outpatient Visit Codes (2021 Guidelines)

Code	New Patient	Level	Typical Time

|------|-------------|-------|-------------|

99202	New	Low complexity	15-29 min
99203	New	Low complexity	30-44 min
99204	New	Moderate complexity	45-59 min
99205	New	High complexity	60-74 min
99211	Established	Minimal	May not need MD
99212	Established	Low complexity	10-19 min
99213	Established	Low complexity	20-29 min
99214	Established	Moderate complexity	30-39 min
99215	Established	High complexity	40-54 min

New vs Established Patient:

•New patient — has not received professional services from the physician (or physician of same specialty in same group practice) within the past 3 years

•Established patient — has received professional services within the past 3 years

Medical Decision Making (MDM) — Key to E/M Selection

Since 2021, E/M level is based on either MDM OR total time:

How an E/M Level Actually Gets Assigned

Visit Documented

Provider records the encounter

Score by Time OR MDM

Total time spent, or 2 of 3 MDM elements

E/M Level Assigned

Low / Moderate / High → specific code

MDM has 3 elements (need 2 of 3 to meet level):

1.Number and complexity of problems addressed

2.Amount and/or complexity of data reviewed

3.Risk of complications and/or morbidity or mortality

Level	Problems	Data	Risk

|-------|---------|------|------|

Low	2 stable chronic	Limited	Low (OTC drugs, minor surgery)
Moderate	1 undiagnosed new problem	Moderate	Moderate (Rx drugs, minor surgery with risk)
High	1 chronic with severe exacerbation	Extensive	High (drug therapy requiring monitoring)

Surgery Section — Key Concepts

Global Surgical Package

When you bill a surgical code, it includes:

•Pre-operative visit (1 day before major surgery, same day for minor)

•The operation itself

•Post-operative visits for the global period

- Minor surgery: 10 days

- Major surgery: 90 days

What is NOT included (can bill separately):

•Treatment of unrelated conditions during global period

•Complications requiring return to OR

•Diagnostic tests, lab work

•Assistant surgeon services

Modifiers — Critical for Surgery

A modifier is a two-character code appended to a CPT code (like -25 or -59) that tells the payer a service was altered in some specific way — without changing what the core procedure actually was. It doesn't replace the CPT code; it adds context the payer needs to process the claim correctly (e.g., "this wasn't a duplicate bill, it was genuinely two separate procedures").

-22  Increased procedural services (unusual complexity — needs documentation)
-24  Unrelated E/M during postoperative period
-25  Significant, separately identifiable E/M same day as procedure
-26  Professional component only (radiology reads)
-47  Anesthesia by surgeon
-50  Bilateral procedure
-51  Multiple procedures (applied to secondary procedures)
-52  Reduced services
-53  Discontinued procedure
-57  Decision for surgery (E/M on day before or day of major surgery)
-58  Staged/related procedure during postop period
-59  Distinct procedural service (override bundling)
-TC  Technical component only
-76  Repeat procedure by same physician
-78  Unplanned return to OR during postop period
-79  Unrelated procedure during postop period
-80  Assistant surgeon
-RT  Right side
-LT  Left side

Common CPT Code Examples

The codes below are long-standing, high-frequency codes used for illustration. CPT is revised annually (new edition each January 1) — verify any code, descriptor, or global-period detail against the current-year CPT codebook before using it in real billing, especially for less common or recently-revised codes.

Office Procedures

10060   Incision and drainage of abscess (simple)
10061   I&D abscess (complicated)
11100   Biopsy of skin (first lesion)
11055   Paring/cutting of benign hyperkeratotic lesion (1-4)
17000   Destruction of premalignant lesion (first lesion)
17110   Destruction of benign lesions (up to 14)

Injections

20610   Arthrocentesis, aspiration/injection major joint (knee, shoulder, hip)
20600   Arthrocentesis small joint (finger, toe)
96372   Therapeutic injection IM or SubQ
96374   Therapeutic injection IV push, single drug
90471   Immunization administration (first vaccine)
90472   Each additional vaccine administration

Common Surgical

27447   Total knee arthroplasty (TKA)
27130   Total hip arthroplasty (THA)
43239   Upper GI endoscopy with biopsy
45378   Colonoscopy, diagnostic
45380   Colonoscopy with biopsy
49505   Repair inguinal hernia (age 5+, initial, reducible)

Radiology

71046   Chest X-ray, 2 views
72148   MRI lumbar spine without contrast
70553   MRI brain with and without contrast
93000   Electrocardiogram (EKG/ECG)
93306   Echocardiography with Doppler

Bundling and NCCI Edits

The National Correct Coding Initiative (NCCI) identifies procedure code pairs that should not be billed together because one is considered part of the other.

Column1/Column2 Bundling — Can Modifier -59 Override It?

Two codes billed together

e.g. 27447 TKA + an intra-op injection

NCCI edit found?

Component bundled into comprehensive code

Were they truly distinct?

Separately supportable by documentation

Bill separately with -59

Only if genuinely distinct — else stays bundled

Two different bundling patterns show up in practice:

1. Column1/Column2 NCCI edits — a component procedure is bundled into
   a more comprehensive one performed at the same session
   (e.g. 27447 TKA includes certain intra-operative injections at
   the same site). Modifier -59 (or the more specific X{E,P,S,U}
   modifiers) overrides the edit only when the two procedures were
   truly distinct and separately supportable by documentation.

2. Mutually-exclusive alternatives, not bundling — 45380 (colonoscopy
   with biopsy) is reported INSTEAD OF 45378 (diagnostic colonoscopy)
   when a biopsy is performed during the same colonoscopy; they are
   not both billed with a modifier, because 45380 already represents
   the "diagnostic colonoscopy that included a biopsy."

Always check current NCCI edit tables (updated quarterly by CMS)
rather than assuming a bundling relationship from memory.

CCI Modifier Indicators

0 = Never use modifier to override (can never bill together)
1 = May use modifier to override if clinically appropriate
9 = N/A

Interview Questions

What is the difference between CPT modifier -25 and -57?

Both are used when an E/M is billed on the same day as a procedure. Modifier -25 is used when the E/M is a significant, separately identifiable service on the same day as a minor procedure (10-day global or 0-day global). Modifier -57 is used when the E/M led to the decision to perform a major surgery (90-day global period) — it can be used on the day of or day before major surgery.

What does "new vs established patient" mean for E/M coding?

A new patient has NOT received professional services from the physician or another physician of the same specialty in the same group practice within the past 3 years. An established patient HAS received such services within 3 years. If uncertain, default to new patient. The distinction matters because new patient codes (99202-99205) generally pay higher than established (99212-99215) and have different documentation requirements.

What is the global surgical package?

The global surgical package is the bundled payment for surgical services. It includes the pre-op visit (1 day for major, same day for minor), the surgery itself, and all routine post-op visits during the global period (90 days for major surgery, 10 days for minor). Billing a separate E/M for a routine post-op visit during the global period is incorrect. You CAN bill separately for complications, unrelated conditions, diagnostic tests, and staged procedures (modifier -58).

Try It (2 Minutes)

Using the code structure table above:

1.A patient gets a chest X-ray. Which of the 6 sections (E/M, Anesthesia, Surgery, Radiology, Pathology/Lab, Medicine) does that fall under, and roughly which code range?

2.A patient has an established-patient office visit for a routine follow-up (moderate complexity, ~35 minutes). Using the E/M table above, which specific code fits?

3.Is that visit's code a "new patient" or "established patient" code, and how can you tell from the code number alone (not just the label)?

You should land on: Radiology (70010–79999) for the X-ray; 99214 for the established-patient moderate-complexity visit; and established-patient codes are the 992-1x range while new-patient codes are 992-0x — the pattern itself is worth recognizing, not just the individual code.

CPT Codes — Overview