Medical Coding — Modifiers & HCPCS Level II flashcards
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The modifiers coders use most (25, 57, 24, 78, 79, 58, 50, 51, 59 and the X modifiers, 76, 77, 91, assistant and co-surgeon), anatomic and liability-notice modifiers, and HCPCS Level II structure and sections.
Learn deck · part of Medical coding: AAPC CPC and AHIMA CCA · written against: ICD-10-CM Official Guidelines and code set FY 2027 (effective 1 October 2026); CPT structure and E/M guidelines described in our own words; HCPCS Level II, NCCI and ICD-10-PCS per CMS. Updated 2026-10-10.
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What does modifier 25 tell the payer?A significant, separately identifiable E/M service was provided by the same practitioner on the same day as a procedure or other service.Modifiers › Global Surgery and E/M
The E/M must go beyond the usual pre- and post-procedure work, though it may share a diagnosis with the procedure. -
A patient comes in for a scheduled mole removal; the physician confirms the plan and removes it. Can an E/M with modifier 25 be billed?No: deciding to do a minor procedure, and the usual work before it, are part of the procedure.Modifiers › Global Surgery and E/M
Modifier 25 needs separately identifiable work, such as evaluating a new, unrelated complaint. -
A surgeon evaluates an ED patient and decides on an emergency colectomy the same day. Which modifier goes on the E/M?Modifier 57, decision for surgery, because the visit led to a major (90-day global) operation that day or the next.Modifiers › Global Surgery and E/M
Watch out: for a minor procedure (0- or 10-day global), Medicare counts the decision to operate as part of the procedure; only a significant, separately identifiable E/M is billed, with modifier 25. -
During the 90-day global after knee surgery, the surgeon treats the patient's unrelated bronchitis. Which modifier goes on the visit?Modifier 24, unrelated E/M by the same practitioner during a postoperative period.Modifiers › Global Surgery and E/M
The diagnosis code should show that the visit is unrelated to the surgery. -
Thirty days into a 90-day global period, the same surgeon performs an unrelated procedure on the same patient. Which modifier goes on the second procedure?Modifier 79, an unrelated procedure by the same physician during the postoperative period.Modifiers › Global Surgery and E/M
Watch out: modifier 78 is an unplanned return to the operating room for a related problem, and modifier 58 is a staged or planned related procedure. -
How is a HCPCS Level II code built, and who maintains it?One letter followed by four digits, maintained by CMS.HCPCS Level II › Structure
Level II covers products, supplies and services that CPT does not, such as ambulance, DME, drugs and orthotics. -
How often is HCPCS Level II updated?Quarterly, with the main annual update on 1 January.HCPCS Level II › Structure
CMS posts each update as an alpha-numeric HCPCS file. -
What happened to HCPCS Level III local codes?They were eliminated under HIPAA, which requires national standard code sets.HCPCS Level II › Structure
Payers now use national Level II codes, including temporary codes, instead. -
What does the HCPCS Table of Drugs show for each drug?The drug's names, the amount of drug per code unit, the route of administration and the HCPCS code.HCPCS Level II › Structure
Route abbreviations include IV, IM, SC, IT, INH, ORAL, OTH and VAR. CMS last published the table with its April 2022 HCPCS files. -
When is a not-otherwise-classified HCPCS code, such as J3490 for unclassified drugs, used?When no specific Level II code describes the item or drug.HCPCS Level II › Structure
The claim must describe the item, such as the drug's name and dosage (many payers also ask for the NDC), so the payer can price it manually.
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About these cards
Review status: Second-reader reviewed, with corrections applied.
Checked against:
- HCPCS Level II codes and modifiers, NCCI policies and Medicare payment rules checked against CMS publications (public domain): the October 2026 alpha-numeric HCPCS file, the Medicare NCCI Policy Manual (2026) and the Medicare Claims Processing Manual, Chapters 4, 5, 8, 12, 14, 16, 18, 20, 23 and 26.
- CPT® is a registered trademark of the American Medical Association. No CPT descriptors are reproduced; CPT structure and guidelines are described in our own words.
- CPC® is a registered trademark of AAPC, and CCA is a credential of AHIMA; neither is affiliated with, or endorses, this product.
These are independent study notes written for Willys. They are not official exam material, may contain mistakes, and are no substitute for your course, your teacher or the exam owner's own publications. Found an error? Tell us — corrections ship as a new version of the deck.
Not coding, billing or compliance advice. These cards prepare you for a certification exam. Code sets change every year, so code real claims from the current ICD-10-CM, CPT® and HCPCS books and your payers' policies. No CPT descriptors are reproduced here.
CPT® is a registered trademark of the American Medical Association; no CPT descriptors are reproduced. CPC® is a registered trademark of AAPC, and CCA is a credential of AHIMA; neither is affiliated with, or endorses, this product.
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