Chapter 14 — Further Reading

Tier 1 — Verified canonical sources

The CPT modifier appendix, current edition. The complete list with full descriptors. This chapter is a reading of it and there is no substitute — the descriptors carry qualifications this chapter summarizes.

CPT section guidelines on modifier use. Several sections carry modifier guidance specific to their codes, and the Surgery guidelines in particular address the global-period modifiers in the context of the surgical package. Chapter 13 §13.4 and Chapter 17 §17.1.

CPT Assistant. Subscription. Modifier 25 and modifier 59 are among the most frequently addressed topics in its history, and a great many of the judgment calls in §14.4 and §14.5 have been addressed specifically.

CMS transmittals and Medicare Claims Processing Manual (Publication 100-04) modifier guidance. CMS's modifier instructions are free, detailed, and frequently more operationally specific than CPT's. Chapter 12 of the manual covers physician services.

The X{EPSU} modifiers — CMS established these as more specific alternatives to modifier 59 and published guidance on their use. Read that guidance directly; the four definitions are short and their distinctions matter.

National Correct Coding Initiative Policy Manual, CMS. Free. The manual explains when a modifier may override an edit and when it may not, and it is organized by CPT section. Chapter 21 works from it. If you use modifier 59, this is the document that governs whether you may.

Medicare Physician Fee Schedule relative value file, CMS. Free. Carries, per code: the global period indicator (000, 010, 090, XXX, YYY, ZZZ), the bilateral surgery indicator, the professional/technical component indicator, and the multiple procedure indicator. Four questions this chapter raises are answered by columns in one free file, and most coders have never opened it.

OIG Work Plan, updated monthly, and published OIG reports on evaluation and management services billed with modifier 25. The documented basis for Case Study 1.

Individual payer provider manuals and reimbursement policies. For modifiers more than for almost anything else in this book, the payer's own published policy is the operative source — bilateral reporting conventions, modifier 25 handling, and X{EPSU} acceptance all differ materially.

Tier 2 — Attributed, specifics unverified

AAPC and AHIMA material on modifier application, particularly on the 25/57 distinction and the global-period set. Both organizations publish substantial free content, and the global-period modifiers benefit from a second explanation.

Specialty society coding guidance on modifiers. Surgical specialties in particular publish practical material on the global-period modifiers, and it is frequently better than general material because it works from real operative scenarios.

Commentary on payer modifier 25 policies, including physician organization responses to proposed automatic reductions. Case Study 1 describes this as a contested area, and reading the arguments on both sides is worthwhile — a coder who understands the payer's position writes better appeals.

Published analyses of modifier utilization, including comparisons of modifier 25 and 59 rates across providers and specialties. Useful for understanding what "outlier" means in practice. Treat specific figures as study-specific and measure your own.

Compliance guidance on automatic modifier application. §14.1's compliance callout describes a common configuration and a common exposure; the compliance literature on edit and modifier automation is practical and worth reading if you are responsible for a billing system.

Tier 3 — Illustrative and constructed

All scenarios in this chapter — the four modifier 25 scenarios in §14.4, the modifier selection exercises, and the decision trees in §14.9 and §14.11.

Case Study 2 in its entirety — the ophthalmology practice, the three bilateral conventions, the four years, and the timely-filing recovery limit. Constructed; the mechanism and the payer variation are real.

Account 10-4471's modifier analysis and the Q1 resolution.

Two things worth doing

Open the Medicare Physician Fee Schedule relative value file and find one code you bill often. Look at its global period indicator, its bilateral indicator, its professional/technical indicator, and its multiple procedure indicator. Four modifier questions, answered by four columns, in a free file.

Then read your two largest payers' published policies on modifier 25 and on bilateral reporting. Twenty minutes each. Case Study 2 is what happens when nobody does, and §14.4's day-17 denial on Account 10-4471 is a payer policy that a coder is much less frustrated by once they have read it.