Chapter 13: CPT Structure: Sections, Guidelines, Symbols, and the Anatomy of a Code

"The codes are the part everyone reads. The guidelines are the part that decides the argument." — constructed

Overview

ICD-10-CM said what was wrong with the patient. CPT says what was done about it — and CPT is where the money is.

That is not cynicism. It is structure. On the professional claim that most coders spend most of their careers on, the procedure code determines the dollar amount and the diagnosis code determines whether the payer agrees the amount was warranted. Get the diagnosis wrong and the claim is denied. Get the procedure wrong and the claim is underpaid, overpaid, or — in the case that ends careers — paid for something that did not happen.

Part III is seven chapters. This one is the architecture, and it makes an argument that will sound like exaggeration until you open a book and check:

The most valuable part of CPT is the part almost nobody reads.

Not the codes. The guidelines at the front of each section and subsection, the parenthetical notes tucked under individual codes, and the symbols in the margin. Those three things change what a code means, forbid combinations, require companions, and settle disputes — and a coder who navigates by the index and the descriptor alone will never encounter any of them.

One structural difference from Part II worth stating up front. ICD-10-CM is maintained by federal agencies and published free. CPT is a copyrighted work of the American Medical Association, sold rather than distributed, and that single fact shapes the code set's governance, its update cycle, its cost to you personally, and what this book is allowed to reproduce.

In this chapter, you will learn to:

• Explain what CPT is, who maintains it, and what its being copyrighted means for you
• Distinguish Category I, II, and III, and know when a Category III code is mandatory
• Name the six sections and their ranges
• Read a section guideline and say why it governs
• Identify every symbol and what it warns you about
• Find the instructions hiding in parentheticals
• Recognize add-on and modifier-51-exempt codes
• Apply "separate procedure" correctly

Learning Paths

🎓 Certification — All of it. §13.5 (symbols), §13.7 (add-on codes), and §13.8 (separate procedure) are guaranteed content, and the exams are open book precisely because navigation is the skill being tested.

💼 New Coder — §13.4 is the chapter. Read it, then go read one section guideline in your own book, then come back.

💵 Biller / AR — §13.6 and §13.7 explain a whole category of denial: codes that may not be reported together, and codes that may not be reported alone.

🏥 Practice Manager — §13.1's cost discussion is real and affects hiring and training budgets. §13.2's Category III material matters if your practice does anything new.

13.1 What CPT is, who owns it, and why that matters

Current Procedural Terminology is the code set describing procedures and services furnished by physicians and other qualified health care professionals. It is HCPCS Level I (Chapter 6 §6.1), and it is maintained by the American Medical Association.

Governance

The CPT Editorial Panel — a body appointed by the AMA Board of Trustees, including representatives of physician specialty societies, of CMS, of health plans, of hospitals, and of performance measurement organizations — meets several times a year to consider proposals to add, revise, or delete codes. It is advised by the CPT Advisory Committee, drawn largely from national medical specialty societies.

The process is open in the sense that anyone may submit an application, and the panel's agendas and actions are published. It is not open in the sense that the resulting code set is free.

A separate body values the codes. The AMA's Relative Value Scale Update Committee — universally called "the RUC" — makes recommendations to CMS about the relative value units assigned to codes. That is a different committee doing a different job, and Chapter 23 §23.2 takes it up. Keep the two separate: the Editorial Panel decides what the codes are; the RUC recommends what they are worth.

The update cycle

CPT changes every January 1. New codes, deleted codes, revised codes, revised guidelines, revised parentheticals.

And the most dangerous change is the one that leaves the number alone. Chapter 6 §6.7 said it and this is where it bites hardest: a code whose descriptor changed while the five digits stayed the same produces no rejection at all. You bill the right number for the wrong service and the claim pays.

The copyright, stated plainly

CPT is a copyrighted work and the AMA licenses its use. Practical consequences:

A current professional edition costs money, every year. For a student that is a real barrier and this book has said so before (Chapter 6 §6.1). A prior year's edition is a legitimate and common way to learn the structure cheaply — and you must never bill from it.

Software that contains CPT is licensed. Encoders, practice management systems, and clearinghouses all pay for it, and it is part of what you are buying.

And this textbook cannot reproduce the code set. It discusses individual codes and paraphrases descriptors for teaching, which is what an educational work may do. It does not print long verbatim descriptor runs, does not reproduce sections, and is not a substitute for a licensed current codebook. Where this book and the CPT book disagree, the CPT book is right.

⚖️ Compliance Check

Two licensing realities worth knowing before you start a job.

You need a current book or a licensed encoder. Coding from a prior-year edition is not a technicality — codes are deleted and descriptors change, and billing a deleted code or a re-described one is a claim error regardless of good faith.

And copying substantial portions of CPT into your own materials is a copyright problem, however well-intentioned. Practices build internal cheat sheets, superbills, and training decks that reproduce descriptors, and the licensing terms govern that. If your organization is building internal materials from CPT, someone should have read the license.

This is a summary and not legal advice. Licensing terms change and vary by product; verify with the AMA and with your organization's counsel.

13.2 Category I, II, and III

Three categories, and the third one has a rule that surprises people.

Category II — the codes nobody bills

Category II codes exist to facilitate quality measurement. They describe components of care that a performance measure wants counted — that a particular assessment was performed, that a result fell in a range, that a patient was counseled.

They carry no relative value and are not paid. Reporting them is optional from a payment standpoint, and required by some quality programs.

Which means a coder in a practice participating in quality reporting may be assigning codes that generate no revenue at all, and understanding why is worth a moment: the code is the reporting mechanism for a measure, and the measure affects payment somewhere else entirely. Chapter 36 §36.9 covers the machinery.

Category III — the rule that matters

Category III codes describe emerging technology, services, and procedures. They are temporary: each one is archived after a defined period — the AMA's stated convention is roughly five years — unless it is converted to a Category I code or its retirement is extended.

And here is the rule:

If a Category III code exists that describes the service, it must be used INSTEAD OF an unlisted Category I code.

That is not a preference. A coder who reaches for an unlisted procedure code (§13.9) when a Category III code describes the service has chosen the less specific option, and the guidance is explicit that the Category III code governs.

Why the rule exists is worth understanding: Category III codes are how the code set collects utilization data on a new service. If everyone reported unlisted codes instead, there would be no data, and the service could never accumulate the evidence needed to become a Category I code. Using the Category III code is how a new procedure eventually gets a permanent one.

🎓 Exam Watch

Two reliable questions.

Format identification. "A code ending in the letter T is a…" — Category III. Ending in F — Category II. Five digits — Category I.

And the mandatory-use rule: "A Category III code exists that describes the procedure performed. The coder should report…" — the Category III code, not an unlisted Category I code. The distractor is always the unlisted code, because it feels more official.

13.3 The six sections and their boundaries

Look at that table again, because the first thing to notice about it is the thing nobody mentions:

The book is not in numeric order.

Evaluation and Management appears first and carries the highest code numbers. It was moved to the front because it is the most frequently used section, and the numbering was left alone.

This matters practically. A coder flipping through the book looking for a code numerically will not find E/M where they expect it, and a coder who reasons "99214 is a high number so it must be near the end" is wrong about a code they will use every day.

What the section boundaries actually mean

The sections are not watertight, and three overlaps generate real questions:

Surgery and Medicine both contain procedures. The Medicine section is where a great many non-surgical procedures live — injections, infusions, immunizations, cardiovascular studies, ophthalmology, physical medicine. The dividing line is not "invasive versus non-invasive" and is better learned by looking than by reasoning.

Radiology and Medicine both contain imaging-adjacent services. Some cardiac and vascular imaging lives in Medicine.

And Surgery contains services that are not surgery, which surprises people constantly. Account 10-4471's venipuncture is in the Surgery section, under the cardiovascular system. So is the joint injection. Neither is what a lay reader would call surgery, and both are in Surgery because that is where the classification put procedures on the body's structures.

The practical rule: find codes through the index (§13.10), not by reasoning about which section a service "belongs" to. Your reasoning will be sensible and frequently wrong.

What is inside each section

A rough map, worth reading once so that the shape is familiar:

Two observations that pay off later.

The Surgery section is by far the largest, running from 10004 to 69990, and it is organized in head-to-toe body system order the way ICD-10-CM's body-system chapters are. Once you know the Surgery section's order, you can predict roughly where a procedure sits.

And the Medicine section is a genuine grab bag, which Chapter 19 §19.8 says outright. It collects the non-surgical procedural services that did not fit anywhere else, organized by specialty rather than by anatomy — which means finding something in Medicine by browsing is much harder than in Surgery, and the index matters more.

The appendices, and the four that earn their tabs

CPT's appendices carry a substantial amount of practical content, and the specific letters and contents change between editions — appendices have been added, revised, and removed. Check your book's table of contents rather than relying on a remembered letter.

The ones worth tabbing in any edition that has them:

Other appendices carry vascular family definitions, electrodiagnostic nerve listings, products pending regulatory approval, multianalyte assay listings, and telemedicine service listings. Skim the table of contents once; you will not need most of them and you will need one of them urgently at some point, and knowing it exists is the whole benefit.

13.4 Section guidelines: the part everyone skips

This section is the chapter.

At the front of each of the six sections there is a block of guidelines. Within sections, at the front of subsections, there are further notes.

They govern every code beneath them. They define terms, state what is included in the codes, state what may not be reported separately, describe how to handle unusual circumstances, and — repeatedly — answer the exact question a coder is about to get wrong.

And almost nobody reads them, because the index does not take you there. Chapter 8 §8.4's cascade diagram applies identically here: the index drops you at a code, and everything above it still governs.

What is actually in them

Varies by section, and the recurring content:

The Surgery section guidelines are the most consequential in the book, because they define the surgical package — what a surgical code's payment includes and therefore what may not be billed alongside it. Chapter 17 §17.1 works it in full. It is a few paragraphs, it governs thousands of codes, and most people who use CPT daily have never read it.

⚠️ Where Claims Die

The guideline that answered the question you were about to get wrong.

The pattern is always the same. A coder has a genuine question — may these two be reported together? is this included? what if it took twice as long? — searches the internet, asks a colleague, posts on a forum, and gets a plausible answer in twenty minutes.

The answer was in the section guidelines, four pages earlier, and would have taken ninety seconds.

This is not a criticism of asking colleagues. It is an observation about order of operations: the guidelines are the first place to look and they are usually the last place people look, because the index never routes anyone there.

The habit worth building in your first month: when you have a CPT question, before you search anything, turn to the front of the section and skim the guidelines. You will find the answer often enough that the habit pays for itself, and when you do not, you will at least know what the section says about the neighborhood.

13.5 The symbols and what each one warns you about

CPT uses a set of symbols in the margin and inline. Each one is a warning, and ignoring them produces a specific error.

Symbol sets vary slightly between editions and publishers, and additional symbols exist — including markers for products pending regulatory approval. Your book has a symbol key, usually on the inside cover or in the front matter. Find it and read it once.

The two that matter most

The triangle (▲) is the one to fear. A revised code is the failure mode Chapter 6 §6.7 and §13.1 both flagged: the number survives and the meaning changes. Nothing rejects. The claim pays. And you have billed a service that was not furnished — not through any error of judgment, but because you were using knowledge that expired on January 1.

The habit: in January, look at every ▲ on the codes your practice actually bills. It is a short list and it is the single highest-yield hour of the update cycle.

The number sign (#), which you will also hear called the pound sign, is the one that confuses people. CPT resequences codes — placing a code out of numeric order so it sits with related codes rather than where its number would put it. The code is completely valid; it is just not where you would look for it numerically.

Which is another reason to use the index rather than flipping. And there is an appendix listing the resequenced codes, which is worth knowing exists.

🎓 Exam Watch

Symbol identification is guaranteed, and it is free points if you have read the key.

The two most-asked: + means add-on code (never reported alone, exempt from modifier 51) and ⊘ means modifier 51 exempt.

The trap: candidates conflate them. All add-on codes are modifier-51 exempt, but not all modifier-51-exempt codes are add-on codes. They are two different lists in two different appendices, and a code can be on the second without being on the first.

13.6 Parenthetical notes and the instructions hiding in them

Underneath and around individual codes, CPT prints instructions in parentheses. They are easy to skim past and they are binding.

The kinds

Cross-references. "(For X, see 12345.)" — you are in the wrong place, here is the right one.

Prohibitions. "(Do not report 12345 in conjunction with 67890.)" — these two may not be reported together. This is a bundling instruction living in the code book itself, independent of the NCCI edit files (Chapter 21), and it is binding whether or not an edit exists.

Requirements. "(Use 12345 in conjunction with 67890.)" — an add-on code's primary, or a required companion.

Conditional instructions. "(If imaging guidance is performed, use 12346.)" — a different code applies under different circumstances.

Deletion notices. "(Code 12345 has been deleted. To report, use 67890.)"

Why they are missed

Because they are typographically quiet and physically small, and because a coder reading a descriptor has already found what they came for. The parenthetical is below the thing you were looking for, in smaller type, in a font that reads as a footnote.

And they are frequently the most operationally important text on the page.

📋 Read the Chart

text FIGURE 13.1 — "What the parenthetical says" [constructed teaching example, modeled on real CPT layout] THE DOCUMENT A page of the CPT Surgery section, musculoskeletal subsection, at the joint injection codes. Rendered schematically -- descriptors paraphrased, not reproduced. THE CONTEXT A coder has found the code for a major joint injection and is about to assign it. WHAT IT SHOWS Two codes distinguished by ONE variable: whether ultrasound guidance was used and permanently recorded. And two parentheticals: one directing the coder to the other code when guidance is used, and one prohibiting reporting both for the same joint. WHAT IT DOESN'T It does not say what happens if guidance was used and NOT permanently recorded. That is a documentation question the descriptor answers and the parenthetical does not. THE DECISION Read the procedure note for the guidance question BEFORE choosing between the two codes -- not after. THE LESSON Two codes, one variable, and the variable is in the operative note rather than in the assessment. The parenthetical tells you which question to go ask.

```text ┌──────────────────────────────────────────────────────────────────┐ │ 20610 Arthrocentesis, aspiration and/or injection, MAJOR │ │ joint or bursa; WITHOUT ultrasound guidance │ │ │ │ 20611 ... ; WITH ultrasound guidance, │ │ with permanent recording and │ │ reporting │ │ │ │ (Do not report 20610, 20611 in conjunction with one │ │ another for the same joint) ◄── PROHIBITION │ │ │ │ (If ultrasound guidance is performed, see 20611) │ │ ◄── CONDITIONAL │ └──────────────────────────────────────────────────────────────────┘

Descriptors PARAPHRASED. The real entries are longer and carry additional parentheticals. VERIFY IN A CURRENT CPT BOOK. ```

This is the page Account 10-4471 turns on, and §13.10's checkpoint returns to it. The note says "No imaging guidance used." One clause in a procedure note, and it selects between two codes.

13.7 Add-on codes and modifier-51-exempt codes

Two lists, two rules, and they are related without being the same.

Add-on codes — the + symbol

An add-on code describes additional work performed with a primary procedure. It exists only as a supplement.

Three rules:

1. Never reported alone. An add-on code without its primary procedure is an error, and it is one payers detect automatically.
2. Exempt from modifier 51. Add-on codes are not subject to the multiple-procedure reduction (Chapter 18 §18.8), because their values already reflect that they are additional.
3. Their primary procedures are specified, usually in a parenthetical directly beneath them naming which codes they may accompany.

CPT publishes a summary list of add-on codes in an appendix. Know it exists.

Modifier-51 exempt — the ⊘ symbol

A separate designation. Some codes that are not add-on codes are also exempt from modifier 51, because their values already account for the circumstances in which they are performed.

CPT publishes this as its own appendix list, distinct from the add-on list.

   TWO LISTS, ONE RELATIONSHIP

   ┌─────────────────────────────────────────────┐
   │  ADD-ON CODES  ( + )                        │
   │  ► never reported alone                     │
   │  ► exempt from modifier 51                  │
   │  ► primary procedures specified             │
   └──────────────────┬──────────────────────────┘
                      │ ALL add-on codes are
                      │ modifier-51 exempt
                      ▼
   ┌─────────────────────────────────────────────┐
   │  MODIFIER-51 EXEMPT  ( ⊘ )                  │
   │  ► do not append modifier 51                │
   │  ► MAY be reported alone                    │
   └─────────────────────────────────────────────┘

   NOT all modifier-51-exempt codes are add-on codes.
   The relationship runs ONE WAY.

⚠️ Where Claims Die

The add-on code billed alone.

It happens when a primary procedure is not documented, is documented and not coded, or is coded and then removed during a claim correction — leaving the add-on stranded.

It denies, reliably, because the edit is trivial to write and every payer has it.

The subtler version: the primary procedure is on the claim but is not one of the primaries the add-on code may accompany. The parenthetical beneath the add-on code names them, and a coder who did not read it has paired an add-on with an unrelated primary.

And the compliance version, which Chapter 5 §5.8 covered: Account 31-2245's line 2 was an add-on code, correctly reported, and it is worth noting that an add-on code appearing alongside its primary is not unbundling. It is what the code is for. The problem on that claim was line 3.

13.8 "Separate procedure" and what it forbids

A designation appearing in some code descriptors, and the source of a great deal of confusion because the phrase means nearly the opposite of what it sounds like.

What it means

A code designated "(separate procedure)" describes a service that is commonly performed as an integral component of a more extensive procedure.

The rule:

A "separate procedure" code is NOT reported when it is performed as part of a more extensive procedure at the same session and same anatomic site.

It IS reported when it is performed INDEPENDENTLY, or is unrelated to or distinct from other procedures performed at the same session.

Why the name is backwards

"Separate procedure" sounds like permission — this is separate, so report it separately. It is the opposite: the designation is a flag that the service is usually NOT separately reportable, and that reporting it requires the circumstances the second half of the rule describes.

The mental correction that helps: read it as "separate procedure — meaning: only when genuinely separate."

What "distinct" requires

Where a separate-procedure code is reported alongside other procedures, the documentation must support that it was independent, unrelated, or performed at a different site or session. That is a documentation question, and it is frequently the same documentation question that modifier 59 asks (Chapter 14 §14.5) — which is why the two topics travel together and why Account 31-2245's audit (Chapter 5 §5.8) is about both.

🎓 Exam Watch

"Separate procedure" is examined and the question is built on the name.

"A code designated as a separate procedure is reported when…" — when it is performed independently or is unrelated to or distinct from other procedures performed at the same session.

The distractor: "always, because it is separate." That is the reading the name invites and it is wrong.

A second form gives a scenario in which a separate-procedure code was performed as part of a larger procedure at the same site, and asks whether to report it. No.

13.9 Unlisted procedures and the special report

When no code describes the service.

Each section has unlisted procedure codes, generally ending in 99, for services the code set does not yet describe.

Three rules:

1. Use them only when nothing else fits — including Category III. §13.2's rule: if a Category III code describes the service, it must be used instead.

2. They require a special report. CPT's guidelines describe what a special report must contain, and the general shape is: a description of the nature, extent, and need for the procedure, plus the time, effort, and equipment necessary. Some also address complexity of symptoms, final diagnosis, concurrent problems, and follow-up care.

3. They do not price themselves. An unlisted code has no assigned relative value, which means the payer must determine payment individually — usually by comparing it to a similar coded service. The special report is what the payer uses to do that, which is why a thin one produces a low payment or a denial.

Practical consequence: an unlisted code is slow, manual, and frequently underpaid, and that is the honest reason coders avoid them. It is not a reason to use a code that does not describe the service. Reporting an inaccurate but well-paid code because the accurate one is unlisted is a false claim (Chapter 5), and it is a temptation this chapter should name rather than pretend away.

13.10 The CPT Index, and why it is not the answer

CPT has an index, and Chapter 8's two-step rule applies here with the same force.

How it is organized

The index is arranged by main terms of four kinds:

Note the difference from ICD-10-CM. In ICD-10-CM, main terms are conditions and looking up a body part gets you "see condition" (Chapter 8 §8.2). In CPT, the anatomic site is a legitimate entry point, because a procedure is done to something.

That is a real difference between the two books and it trips people who learned ICD-10-CM first.

What the index gives you

A code, or a range of codes, or a cross-reference.

A range is the index telling you it cannot decide. "Arthrocentesis … 20600–20611" means the right code is in there and the distinguishing variable is something the index does not know — joint size, guidance, aspiration versus injection.

The rule

Never code from the index.

Go to the code in the body of the book, and read:

• the descriptor, completely, including everything after the semicolon
• the parenthetical notes beneath it (§13.6)
• the subsection guidelines above it (§13.4)
• the symbols in the margin (§13.5)

None of those is in the index, and any one of them can change the answer.

The semicolon convention

One typographic feature that causes real errors.

CPT saves space by using a semicolon to split a descriptor into a common portion and a unique portion. The common portion appears in the first code of a family; subsequent codes are indented and carry only their unique portion.

   HOW THE SEMICOLON WORKS

   20600   Arthrocentesis, aspiration and/or injection, small joint
           or bursa; without ultrasound guidance
                                 └── everything BEFORE the semicolon is
                                     the COMMON portion

   20604            ; with ultrasound guidance, with permanent
                      recording and reporting
           └── the indented code inherits EVERYTHING before the
               semicolon from the code above it

   READ IT AS:  "Arthrocentesis, aspiration and/or injection, small
                 joint or bursa; with ultrasound guidance, with
                 permanent recording and reporting"

A coder who reads only the indented portion has read a fragment. The full descriptor is the common portion plus the unique portion, and the common portion is above — sometimes several codes above, and sometimes on the previous page.

This is the single most common reason a coder assigns a code whose descriptor does not match the service. They read the indented text, it fit, and the inherited half did not.

🗂️ The Encounter

🗂️ The Encounter

What this chapter contributes: locating three codes in the CPT structure, and finding the subsection guideline that governs the injection.

```text ACCOUNT 10-4471 — where the procedure codes live

99214 ► SECTION: Evaluation and Management (99202-99499) SUBSECTION: Office or Other Outpatient Services CATEGORY: Established patient

       ◄── AND NOTICE: E/M is the FIRST section in the book
           and carries the HIGHEST code numbers. A coder
           flipping numerically will not find it. §13.3

20610 ► SECTION: Surgery (10004-69990) SUBSECTION: Musculoskeletal System HEADING: General SUBHEADING: Introduction or Removal

       ◄── A joint injection is in the SURGERY section. Not
           because it is surgery in any lay sense, but
           because that is where procedures on the body's
           structures are filed. §13.3

36415 ► SECTION: Surgery (10004-69990) SUBSECTION: Cardiovascular System HEADING: Arteries and Veins

       ◄── A VENIPUNCTURE is in the Surgery section. This
           is the example that breaks everyone's intuition
           about what "Surgery" contains.

J1030 ► NOT IN CPT AT ALL. HCPCS Level II. Chapter 20. ```

The guideline that governs 20610. Two layers, and both matter.

The Surgery section guidelines define the surgical package — what is included in the payment for a surgical code, and therefore what may not be reported separately alongside it. That definition is what makes the Chapter 21 edit question askable at all, and Chapter 17 §17.1 works it in full.

The Musculoskeletal subsection notes carry the specifics for this family, and the operative instruction for this file is the parenthetical in Figure 13.1:

(If ultrasound guidance is performed, see 20611) (Do not report 20610, 20611 in conjunction with one another for the same joint)

And the note answers it in one clause. Figure 4.2's procedure note says:

"…a 22-gauge needle was introduced into the joint space. Methylprednisolone acetate 40 mg with 3 mL of 1% lidocaine was injected without difficulty. No aspirate obtained. No imaging guidance used."

Six words select between two codes. Without them, a coder would have to decide whether the absence of any mention of guidance means guidance was not used — which is an inference (Chapter 4 §4.7), and a reasonable coder could go either way.

This is the second time this file has been decided by a documented negative. Chapter 12 found "No known injury" deciding which ICD-10-CM chapter the encounter lives in. Now "No imaging guidance used" decides which of two CPT codes applies. Both are things a physician wrote down that did not happen, and both are load-bearing.

What this settles. Where the three CPT codes live, and which guideline and parenthetical govern the injection.

What it does not settle. The actual code assignments. 99214 requires leveling from the documentation, which is Chapter 15. 20610 requires the modifier question, which is Chapter 14. And whether they may be reported together at all is Chapter 21.

Open questions: Q1 (modifier 25), Q5 (the knee), Q6 (the \$185.00). Q2 partially resolved.

Conclusion

The codes are the part everyone reads. The guidelines are the part that decides the argument.

What was decided in this chapter. That CPT is maintained by the AMA through an Editorial Panel that decides what codes exist, while a separate committee — the RUC — recommends what they are worth, and that it changes every January 1 with the revised code being the dangerous change because the number survives. That it is copyrighted, which costs you money annually, licenses your software, and limits what this book may reproduce. The three categories, and the rule that a Category III code must be used instead of an unlisted code — because that is how a new service accumulates the data to earn a permanent one. The six sections, the fact that the book is not in numeric order, and that Surgery contains a venipuncture. That the section and subsection guidelines govern every code beneath them and that almost nobody reads them, because the index does not route anyone there. The symbols, with the triangle as the one to fear and the resequencing marker as the one that confuses. The parentheticals — cross-references, prohibitions, requirements, conditionals — printed quietly and binding. Add-on codes and modifier-51-exempt codes, two lists whose relationship runs one way. "Separate procedure," whose name means nearly the opposite of what it says. Unlisted codes, the special report, and the honest reason coders avoid them. And the index: a legitimate anatomic entry point, unlike ICD-10-CM's — and never the answer, with the semicolon convention as the single most common cause of a descriptor that did not match.

What remains open. Every code. You know the architecture and have assigned nothing.

The bridge to Chapter 14. Modifiers. Two digits appended to a code, changing what it asserts, what it is worth, and how closely it will be examined. Modifier 25 and modifier 59 are between them responsible for an enormous share of outpatient audit activity in the United States, and both are frequently applied by software rather than by a person reading a note — which Chapter 5's Figure 5.1 already showed costs \$25,720.80 when nobody is looking. Chapter 14 also raises Q1, which has been visible since Chapter 5 and unasked until now.

Key Terms

CPT (Current Procedural Terminology) — the code set describing procedures and services furnished by physicians and other qualified health care professionals; HCPCS Level I, maintained by the American Medical Association, updated every January 1, and copyrighted. (Ch.13)

CPT Editorial Panel — the AMA-appointed body that decides what codes exist, advised by the CPT Advisory Committee. Distinct from the RUC, which recommends relative values. (Ch.13)

Category I — five-digit codes for widely performed procedures and services consistent with contemporary practice. (Ch.13)

Category II — four-digit codes ending in F, for performance measurement. Optional and not paid. (Ch.13)

Category III — four-digit codes ending in T, for emerging technology. Temporary, and must be used instead of an unlisted code where one describes the service. (Ch.13)

Section — one of CPT's six divisions: Evaluation and Management, Anesthesia, Surgery, Radiology, Pathology and Laboratory, and Medicine. The book is not in numeric order. (Ch.13)

Guideline — the instructional text at the front of a section or subsection, governing every code beneath it. (Ch.13)

Parenthetical note — an instruction printed in parentheses near a code: a cross-reference, a prohibition, a requirement, a conditional, or a deletion notice. Binding. (Ch.13)

Add-on code — marked +; describes additional work performed with a primary procedure. Never reported alone, exempt from modifier 51, and its permitted primaries are specified. (Ch.13)

Modifier-51 exempt — marked ⊘; a code to which modifier 51 is not appended. A separate list from the add-on codes; all add-on codes are exempt, not all exempt codes are add-on codes. (Ch.13)

Separate procedure — a designation meaning the service is commonly an integral component of a more extensive procedure. Not reported when performed as part of a larger procedure at the same session and site; reported when performed independently or distinctly. (Ch.13)

Unlisted procedure — a code for a service the code set does not describe. Requires a special report, carries no assigned relative value, and may not be used where a Category III code applies. (Ch.13)

Special report — the narrative accompanying an unlisted procedure code, describing the nature, extent, and need for the procedure along with the time, effort, and equipment involved. (Ch.13)

Resequenced code — marked #; a code printed out of numeric order so that it appears with related codes. (Ch.13)

Semicolon convention — CPT's typographic device splitting a descriptor into a common portion (before the semicolon) and a unique portion, with indented codes inheriting the common portion. (Ch.13)

Spaced Review

1. Name the six CPT sections and their ranges. Which section appears first, and what is unusual about its code numbers?

2. (Chapter 8) State the CPT index rule and name four things you must read at the code that are not in the index.

3. A Category III code exists that describes a service. May the coder report an unlisted Category I code instead? State the rule and the reason for it.

4. A code descriptor reads, indented, "; with ultrasound guidance." What have you not yet read, and where is it?

5. (Chapter 5) An add-on code appears on a claim alongside its primary procedure. Is that unbundling? Explain, referring to Account 31-2245.