CPC STUDY COURSE · 2026 EDITION
A new result after treatment
Read an original fictional chart, identify the supported facts, and explain your coding workflow.
Chart gym · Original fictional record
Service date: 2026-09-09 · Outpatient laboratory; Medicare reporting relationship
Use your code books and write your reasoning before opening the walkthrough. This exercise contains no real patient information.
Initial care
Fictional adult receives an ordered clinical laboratory test in an outpatient treatment setting. The initial result is valid and is reported to the treating practitioner. The test is payable under the Medicare clinical laboratory fee schedule for this exercise.
Later order
After documented treatment, the practitioner orders another measurement of the same analyte that afternoon to assess response. A later specimen is collected and processed. This is not a rerun of the first specimen, a confirmation step or a correction of instrument failure.
Reported results
The record contains two clinically needed results at distinct treatment points. Each result has its collection time and practitioner order. Assume that no standard current entry already describes this series and that the other coverage and reporting requirements are met.
Coding review
The learner must identify the modifier specifically described for an applicable repeated clinical laboratory test under the cited Medicare instruction. This focused modifier exercise does not permit adding repeat units when a defined series entry applies or when only one result is required.
Your coding worksheet
- Identify the purpose of the second result.
- Explain why this differs from confirmation.
- Select the applicable repeat modifier.
- Name the defined-series limitation.
In your notebook, record the supported facts, your index route, the instructions you checked, and any missing detail that limits your answer.
Compare with the worked explanation
- The later result evaluates the response to treatment.
- Both results are clinically needed; the second is not a quality-control rerun.
- The cited clinical laboratory fee schedule instruction identifies modifier 91.
- Use the complete defined-series entry when one applies instead of splitting it into repeated single tests.
Reference sections: 100.5.1
Practice the linked chart questions
Review the lesson
Sources
- CMS — Medicare Claims Processing Manual Chapter 16: Laboratory Services. Current consolidated manual accessed September 2026. Accessed 2026-09-10.