Patient Responsibility: Deductibles, Copays, and Coinsurance
Patient responsibility is the share of the allowed amount the plan assigns to the member rather than paying itself. It comes in three forms, it is decided by the plan and not by you, and the entire billing discipline around it is billing exactly that and nothing else.
Updated 6 min read
Reviewed by Anwaar Tayyab
Director of Billing Operations ·
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Key takeaways
- Three forms: a deductible (paid before the plan starts paying), a copay (a fixed amount), and coinsurance (a percentage of the allowed amount).
- All three come out of the allowed amount, not the billed charge. A deductible and coinsurance are calculated from it, so the contract that cut your charge also cut those; a copay is a fixed amount and does not move with it.
- The plan decides it and the remittance reports it. A patient asking why their bill is what it is has usually asked the wrong party.
- Billing a patient for an amount the group code assigned elsewhere is a compliance problem, not a service one.
The three forms, and how they stack
Cost sharing is a benefit design. The plan decides, when it adjudicates, how much of the allowed amount it keeps and how much it hands to the member — and it does that using three mechanisms that behave quite differently.
| Form | How it works | What it means in practice |
|---|---|---|
| Deductible | An amount the member pays before the plan begins paying at all. | Early in a plan year, a claim can be allowed in full and pay nothing — the whole allowed amount goes to the patient. That is a correctly processed claim, not a denial. |
| Copay | A fixed amount for a service, regardless of the allowed amount. | Predictable, and the one patients understand. It does not move with the price of the service. |
| Coinsurance | A percentage of the allowed amount. | Moves with the contracted rate — so the same service costs the patient different amounts under different plans, and neither the practice nor the patient chose that. |
They can appear together on one claim. Many plans also carry an out-of-pocket maximum sitting over all three: once a member reaches it, cost sharing stops for covered services and the plan pays the full allowed amount. That is a feature of the plan rather than a universal rule — Original Medicare, for one, has no out-of-pocket maximum — but where it exists it is why an identical service can be entirely the patient's in January and entirely the plan's in November.
This is why the same patient owes different amounts all year
It comes out of the allowed amount
All three forms come out of the allowed amount — never out of the billed charge. A deductible and coinsurance are calculated from it; a copay is a fixed amount rather than a calculation, but it too is taken out of the allowed amount instead of added on top of it. From Billed Charge to Collected Dollar works through why, and what follows from it. What matters here is only the consequence for billing: the patient's share is carved out of the allowed amount alongside the plan's, so the figure you bill has to come from the remittance rather than from a percentage of your own charge.
The line between an adjustment and a balance is a compliance line
The EOB is not a bill, and it will be read as one
An EOB is the plan's explanation to the member of how a claim was processed. It is not a request for payment, it says so, and patients read it as a bill anyway — because it arrives from an insurance company, carries dollar amounts, and shows an amount labeled as theirs.
Treat that as a given rather than a misunderstanding to correct. Where the EOB reaches the patient before the practice's statement does, their first information about what they owe comes from a document the practice did not write, in language the practice did not choose, at a moment the practice does not control. By the time the statement arrives, they have already formed a view — and if the two documents disagree in any visible way, the practice's is the one that looks wrong.
The useful posture is translation, not correction
Where this article stops
Everything above is operational: what the plan decided, what the remittance reported, and billing that faithfully. There is a second set of questions that looks adjacent and is not — what a patient may be billed when a service is non-covered, what happens when a provider is out of network, what protections apply in particular situations, and what obligations a practice has to offer financial assistance.
Those are legal questions, not operational ones. They turn on the payer contract, on state law, and on federal rules, and they change — so they belong with the practice's own counsel and the specific agreement in front of them rather than with a general answer on a website. This site does not publish legal guidance.
One operational rule that is safe to state
Common questions
Which of the three applies to a given claim?
Whichever the plan's benefit design says, and often more than one — a claim can carry a deductible amount and coinsurance together. You do not work it out; the plan calculates it during adjudication and the remittance reports the result. That is the whole discipline here: bill the figure the remittance assigned rather than deriving one yourself.
A patient says their EOB is wrong. What do we do?
First establish what they are holding. An EOB is the plan's explanation of how it processed the claim — it is not a bill, though it arrives from an insurer with dollar figures on it and is routinely read as one. Confirm that your statement matches the amount the plan assigned as patient responsibility. If it does, the disagreement is with the plan's coverage decision, which the practice did not make and cannot change. If it does not match, the error is on your side and is almost always a posting error.
Can we bill the patient while the secondary claim is pending?
It is a bad idea operationally, whatever else is true. Until the plans that owe something have paid, the patient's final responsibility is not known — so a statement sent now is likely to be wrong, and produces a correction, possibly a refund, and a call that need not have happened. Wait for the coverage to settle, then bill what the remittance assigned. What a patient may be billed in less clear-cut situations is a legal question for your counsel and your contract, not one this site answers.
Key terms in this article
Defined once, on their own pages.
Continue learning
Where to go next.
From Billed Charge to Collected Dollar
The arithmetic that produces the patient's share.
Secondary Billing and Coordination of Benefits
What happens to the balance before any of it reaches the patient.
How Payment Posting Works
Where the patient's balance is decided — and where it goes wrong.
Hematology billing
The one Medicare cost-share counted in units of a physical product, which a patient may discharge by replacing it rather than paying for it.
Reading a Denial
The group codes that separate a write-off from a balance.
Authoritative sources
- Glossary of Health Coverage and Medical Terms (opens in a new tab)
CMS. The federal uniform glossary that accompanies the Summary of Benefits and Coverage. Defines the allowed amount as the maximum payment the plan will make for a covered service; a deductible as an amount owed during a coverage period before the plan begins to pay; a copayment as a fixed amount paid for a covered service; coinsurance as a share calculated as a percentage of the allowed amount; and the out-of-pocket limit, after which the plan usually pays the full allowed amount for covered services. Its balance-billing entry describes the gap between the billed charge and the allowed amount as the balance a plan does not cover, and states that a network provider may not balance bill a member for covered services.
- Medicare & You, the official Medicare handbook (opens in a new tab)
CMS. The Original Medicare side of the same mechanics. States that for Part B-covered services the beneficiary usually pays a percentage of the Medicare-approved amount after meeting the deductible, that there is no yearly limit on what a beneficiary pays out of pocket under Original Medicare absent other coverage, and that the Medicare Summary Notice is not a bill but a statement of what Medicare paid and what may be owed the provider.
- FAQs about Patient Financial Communications (opens in a new tab)
HFMA. The association's own answers on its Patient Financial Communications best practices — its position that communication should be understandable to the patient, that provider organizations should hold standard language for the common types of patient financial conversation, and that discussions should be reinforced with written information.
- Medicare Claims Processing Manual, Chapter 22 — Remittance Advice (opens in a new tab)
CMS Internet-Only Manual 100-04. The source of the group codes that assign liability on a remittance. Section 60.1 states that a group code identifies the general category of a payment adjustment, that it must always be used together with a claim adjustment reason code to show liability, and that contractors have no discretion to omit the codes that communicate who is financially responsible for an amount. It defines the contractual-obligation group code as covering adjustments caused by a contractual agreement between payer and payee or by a regulatory requirement, which are generally a write-off for the provider and are not billed to the patient; and the patient-responsibility group code as covering amounts that may be billed to the patient or insured, typically deductible and copay adjustments. Section 30 requires the remittance to balance at the service, claim, and provider levels, with the total paid amount equal to the total submitted charges plus or minus the payment adjustments — so an amount assigned to the patient is one of those adjustments rather than an addition sitting outside them.