Payer billing guides: filing limits, appeals and portals
The same claim can be paid, denied or returned depending on who is billed, which product the patient holds and which state the plan sits in. Each guide below covers one payer from its own manual or regulation, and shows where the limits come from.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026
Government programs
National commercial payers
Blue Cross Blue Shield plans
Medicaid and Marketplace plans
Why does the same claim follow different rules by payer?
Three things change the rule set for a single claim: the payer, the product and the state. A Medicare fee-for-service claim, a Medicare Advantage claim and a commercial claim for the same visit can each have a different filing limit, appeal path and portal.
| Payer type | How the filing limit is set | Example from the official source |
|---|---|---|
| Medicare | One federal rule for all providers | 42 CFR 424.44: file within 1 calendar year after the date of service |
| Medicaid | Each state agency sets its own limit within federal rules | 42 CFR 447.45: the state agency must require claims within 12 months of the date of service |
| TRICARE | Program rule, with different periods overseas | One year in the U.S. and territories, three years in other overseas areas |
| UnitedHealthcare | State requirements and the provider agreement | The 2026 Administrative Guide says limits vary by state and contract |
| Cigna | Participating status of the provider | 90 days participating and 180 days out of network from the date of service |
| Humana | Product and plan billing guide | The 2026 Illinois HMO D-SNP guide states 365 days from the date of service |
The Medicare limit has stated exceptions, such as contractor or agency error and retroactive entitlement, in 42 CFR 424.44(b). The Medicare billing guide lists them with the appeal levels and the MAC for each state.
State law adds a second layer. Medicaid agencies set their own limits, and commercial plans follow the contract. A fully insured plan can fall under a state prompt pay law, while the Missouri Department of Commerce and Insurance notes that state laws do not apply to self-insured employer plans. The state pages carry the Medicaid limit and the MAC for each state.
Numbers in these guides come from the payer's own manual, bulletin or regulation, and each guide names the page and date it was read. For a side-by-side view of the limits we have sourced, use timely filing limits by payer. The general rules behind them are in the rules library, and denial codes are explained in the code library.
Which payer guide do I need?
Start with the payer on the remittance or the insurance card. If the card shows a Blue plan, use the Blue group, and if the member is on a state Medicaid plan run by a managed care company, check both the Medicaid guide and the plan's own guide.
Oscar Health and Blue Shield of California are not written yet and are not listed. A guide is added only after its figures are checked against the payer's published document.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01Do all payers use the same timely filing limit?
No. Medicare uses one federal limit of 1 calendar year after the date of service under 42 CFR 424.44. Medicaid limits are set by each state agency, and commercial limits sit in the payer contract. UnitedHealthcare says its limits vary by state and contract, and Cigna lists 90 days participating and 180 days out of network.
02Where do I find a payer's official billing manual?
Each payer publishes its own provider manual or administrative guide on its provider site, and government programs publish regulations and CMS manuals. Every guide in this library links the exact document it used, such as the 2026 UnitedHealthcare Administrative Guide or 42 CFR 424.44, so you can read the source yourself.
03Why does a Medicare Advantage claim follow different rules than Original Medicare?
Medicare Advantage plans must follow national coverage determinations and local contractor coverage decisions under 42 CFR 422.101, but they set their own contracts, portals and appeal steps. The Medicare Advantage guide covers the federal decision timeframes, reconsiderations and prior authorization limits that apply to plans.
04Does the same payer have different rules in different states?
Often yes. Anthem and Blue plans operate by state and product, Medicaid is run by each state, and CareSource, Molina and Centene Ambetter work under state plans. A limit for one state does not carry to another, so check the guide for the plan and then the state page.
05What should I do when a payer denies a claim for timely filing?
Read the denial against the payer's own rule. Medicare treats a late-filing denial as not appealable, while UnitedHealthcare accepts defined proof of timely filing such as an EDI acceptance report. Gather the original submission proof, check for a stated exception, then follow the dispute steps in that payer's guide.
06How do I know which payer guide applies to a Blue Cross Blue Shield member?
Use the member's home plan, shown by the prefix on the card, since the local plan submits the claim to the home plan under BlueCard. The Blue Cross Blue Shield guide explains home plan and host plan. Plan-specific guides cover Anthem, BCBS of Texas, Florida Blue and Highmark.
A payer rule you cannot pin down?
Book a call and a certified coder will find the rule behind the denial.