Radiology, Pathology/Laboratory, and Medicine Section Coding — Medical Billing & Coding

Objective. Students will assign CPT codes from the Radiology, Pathology/Laboratory, and Medicine sections, applying section-specific guidelines including professional and technical component rules for radiology.

Overview of Three Major CPT Sections

The CPT manual organizes procedure codes into six sections. Three of those sections—Radiology (70010–79999), Pathology/Laboratory (80047–89398), and Medicine (90281–99199 and 99500–99607)—cover a wide range of diagnostic and therapeutic services. Each section begins with its own set of guidelines. Reading those guidelines before you code is not optional; it is the foundation of accurate coding.

Radiology Section: Key Concepts

Complete vs. Limited Studies

Some radiology codes describe a complete study, which images all required anatomic elements as defined by CPT. A limited study covers fewer elements—for example, a limited ultrasound of the abdomen images only selected organs rather than all abdominal structures. The CPT code you choose must match the scope of the study actually performed and documented. Never code a complete study when the report describes a limited one, because overcoding is a compliance violation.

Professional and Technical Components

Many radiology procedures have two distinct parts:

Technical component (TC): The equipment, supplies, technologist time, and facility overhead needed to produce the image.
Professional component (PC): The physician's work of supervising the study and writing the interpretation report.

When one entity provides both parts—for example, a free-standing imaging center that owns the equipment and employs its own radiologist—the global code (no modifier) is reported. When the parts are split between two entities, each reports only its portion:

Modifier -26 appended to the CPT code = professional component only.
Modifier -TC appended to the CPT code = technical component only.

Example: A hospital owns the MRI scanner. A radiologist who is in private practice (not a hospital employee) reads the scan and sends a written report. The hospital bills the global code with modifier -TC; the radiologist bills the same code with modifier -26.

Supervision and Interpretation

Certain interventional and fluoroscopic radiology codes include supervision and interpretation (S&I) language in their descriptors. These codes capture the radiologist's role when a surgeon or other physician performs the primary procedure. Do not confuse S&I codes with stand-alone diagnostic imaging codes—read the full descriptor carefully.

Pathology/Laboratory Section: Key Concepts

Qualitative vs. Quantitative Assays

A qualitative test reports whether a substance is present or absent (positive/negative). A quantitative test measures the amount of a substance. CPT often provides separate codes for these two types of testing, and they are not interchangeable. Always check the order and the report to confirm which type of result was produced.

Panels

CPT defines laboratory panels (e.g., a basic metabolic panel) by listing the specific tests that must all be performed for the panel code to apply. If fewer tests are done, code each individual test separately. If more tests are added beyond the panel definition, add those tests as individual codes alongside the panel code. Do not bundle tests into a panel code unless every test in the panel definition was performed.

Surgical Pathology Levels

Surgical pathology codes are assigned based on the level of physician work involved in examining tissue, ranging from gross examination only up to complex microscopic examination. The operative or pathology report must support the level billed.

Medicine Section: Key Concepts

Scope of the Section

The Medicine section is a catch-all for services not captured elsewhere: immunizations, infusions, ophthalmology exams, psychiatric services, physical medicine and rehabilitation, dialysis, and many others. Each subsection carries its own guidelines—always read the subsection introduction.

Vaccine Administration

Immunization coding requires two codes: one for the vaccine product itself (the supply) and one for the administration. If a physician or qualified health professional counsels the patient about the vaccine, an additional counseling code may apply. Age and route of administration affect which administration code is correct.

Add-On Codes and Instructional Notes

The Medicine section contains many add-on codes (marked with a + symbol), which are always reported alongside a primary code and never alone. Pay attention to instructional notes such as "Do not report X with Y"—these notes prevent unbundling and duplicate billing, which are audit triggers.

Patient Safety and Scope-of-Practice Reminders

As a coder, you do not diagnose patients or interpret clinical findings. If a radiology report is unclear—for example, if you cannot determine from the documentation whether a study was complete or limited—query the provider rather than guessing. Upcoding (billing a higher-intensity service than was performed) and downcoding both carry legal and financial consequences, but inaccurate coding can also distort patient records and indirectly affect care decisions. Protect patients by coding only what is documented.

Key terms9

Technical component (TC)The portion of a radiology procedure representing equipment, supplies, and technologist services; reported by appending modifier -TC to the CPT code when billed separately from the professional component.

Professional component (PC)The physician's work of supervising a radiology procedure and writing the formal interpretation report; reported by appending modifier -26 to the CPT code when billed separately.

Global codeA radiology CPT code reported without a component modifier, indicating that one entity is billing for both the technical and professional components.

Supervision and interpretation (S&I)A descriptor phrase in certain radiology codes indicating that the code captures the radiologist's oversight and written interpretation when another physician performs the primary procedure.

Qualitative assayA laboratory test that reports whether a substance is present or absent, yielding a positive or negative result.

Quantitative assayA laboratory test that measures and reports the amount or concentration of a substance in a specimen.

CPT panelA defined group of individual laboratory tests bundled under one CPT code; all component tests listed in the CPT definition must be performed to report the panel code.

Add-on codeA CPT code marked with a plus (+) symbol that is always reported alongside a designated primary procedure code and never reported alone.

Limited study (radiology)A radiology examination that images fewer anatomic elements than required for a complete study, represented by a separate, lower-level CPT code.

In class: Section guidelines annotation: students read the introductory guidelines for Radiology, Pathology/Laboratory, and Medicine sections in the CPT manual, highlighting key rules (supervision and interpretation, complete vs. limited studies, qualitative vs. quantitative assays) and writing margin notes summarizing each rule in their own words. · Radiology component coding exercise: students are given eight radiology report scenarios (X-ray, ultrasound, CT, MRI) and must determine whether to code the complete procedure, the professional component only (modifier -26), or the technical component only (modifier -TC), documenting their reasoning. · Multi-section coding worksheet: students code 12 cases drawn from pathology reports, vaccine administration notes, and specialty medicine encounters (ophthalmology, psychiatry, physical therapy), entering codes into the coding log and flagging any add-on codes or instructional notes encountered.
Materials: AMA CPT Professional Edition (Radiology, Pathology/Laboratory, Medicine sections), radiology report samples, multi-section worksheet (instructor-prepared), student coding log workbook
Check: Multi-section coding worksheet scored at 80% or higher; radiology component exercise must demonstrate correct modifier logic with written rationale for each case.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.