Tertiary Insurance Overpayment: What to Do When the Payer Won’t Take Its Refund
No, you can’t keep it. When a tertiary payer like Aetna pays as if it were secondary, the extra money is still…
Coding & Billing Guides
Coding and billing guides explain the rules that decide whether a claim gets paid: which CPT, HCPCS Level II and ICD-10-CM codes and modifiers to report, what Medicare, Medicaid and commercial payers require, and how a claim moves through the revenue cycle from prior authorization to payment posting.
This category is for billers, coders and practice managers who need code-level and payer-level detail. Coding topics include how to use unlisted CPT codes without triggering an audit, when a Category III code is the better choice than an unlisted code, what to enter in Box 19 of the CMS-1500, the GY modifier on Medicare cosmetic claims and when to use ICD-10-CM Z41.1. Billing workflow topics include the corrected claim resubmission process by payer type, 10-day and 90-day global period rules, billing Medicare as secondary under the CMS anti-markup rule and handling a Medicare MAC prepayment review. New to the field? Start with what medical billing is and how CPT codes work.
Coding & Billing FAQs
What is the difference between CPT and ICD-10-CM codes?
CPT codes, maintained by the American Medical Association, describe the procedures and services a provider performed. ICD-10-CM codes describe the diagnosis or reason for the encounter. Claims need both, linked correctly, so the payer can see that each service was medically necessary for the condition reported.
What is a corrected claim?
A corrected claim replaces or voids a claim the payer has already processed. On an 837P, it uses claim frequency code 7 (replacement) or 8 (void); on a paper CMS-1500, the code goes in Box 22 with the original claim number. Sending it as a new claim often triggers a duplicate denial.
Do commercial payers follow Medicare guidelines?
Not automatically. Many commercial payers adopt parts of Medicare’s approach, such as NCCI-style bundling edits or the CMS-1500 format, but their own contracts and published policies control payment. When a commercial policy is silent or unclear, call the payer and document the reference number and the answer you received.
What Are CPT Codes? Categories, Structure and How They’re Updated
CPT codes are five-character codes from the American Medical Association’s Current Procedural Terminology code set, meaning a standard shorthand that providers put…
What Is Medical Billing? A Plain-English Guide to the Claim Cycle
Medical billing is the process of turning a patient visit into a paid claim, meaning the provider’s services and diagnoses are coded,…
CPT Code for Juvederm Breast Injections (11950-11954): What Billers Need to Know
A coder posted this question in a billing community forum: what CPT code is everyone using for injections of Juvederm Ultra XC to bilateral breasts?
ICD-10 Z41.1 Encounter for Cosmetic Surgery: When to Use It and When Not To
Z41.1 is the ICD-10-CM diagnosis code for Encounter for Cosmetic Surgery. It is a Z code, which means it represents a reason for an encounter rather than a disease or injury.
GY Modifier on Medicare Claims: Cosmetic Procedures Billing Guide
Medicare billers working in cosmetic, aesthetic, and plastic surgery practices encounter the GY modifier regularly. It is one of the most specific and unambiguous modifiers in the Medicare billing system, and using it correctly protects the practice, clarifies patient financial…
Global surgical package guide: reference page on 10-day and 90-day global period billing rules
One of the most common reasons a legitimate, separately payable service gets denied isn’t a coding mistake. It’s a misunderstanding of what’s already bundled into the surgery itself.
Corrected claim resubmission guide. Step by step instructions for corrected claims by payer type.
A corrected claim isn’t the same thing as a new claim, and billing it like one is the fastest way to get it rejected, denied as a duplicate, or stuck in limbo for weeks.
I Called Three Commercial Payers About Patellofemoral Arthroplasty Coding: 27438 vs. 27599
CPT 27599 (unlisted femur/knee procedure) is the more technically accurate code for patellofemoral arthroplasty (PFA). But across three commercial payers I contacted directly, 27438 processes and pays without a flag while 27599 routes into manual pricing at 60–80% of the…
CPT 64772 vs 64999: Thumb CMC Joint Denervation Coding Guide
CPT 64999 is the more defensible billing choice for selective thumb CMC joint denervation. This applies when the surgeon has addressed the superficial radial nerve branches. It also applies when the lateral antebrachial cutaneous nerve branches were treated.