How to Dispute a Medical Bill After Insurance Has Paid

Insurance payment doesn't equal 'final'

When insurance pays a claim, the process isn't over — the provider still sends you a bill for the patient responsibility. Many patients pay that balance without checking it against their EOB. But the EOB is the authoritative document: it shows what was billed, what your plan allowed, and exactly what you owe.

The trap: providers' patient statements and EOBs use different formats, different amounts, and arrive at different times. A statement may arrive before the EOB, or show a balance that includes charges your insurer is still processing. Never pay a statement until you've seen the matching EOB and confirmed the numbers agree.

Your EOB is the truth document

Compare the balance on your bill line by line with the EOB's patient responsibility. If the bill asks for more than the EOB, one of two things is happening: the provider didn't apply your insurance correctly, or the provider is balance billing beyond the allowed amount. Both are disputable.

• The bill's balance exceeds the EOB's patient responsibility.
• A deductible or out-of-pocket max was miscalculated.
• The provider applied your payment to the wrong service.
• A covered service was billed to you as non-covered.
• You were billed for a claim your EOB shows as paid in full.

Deductibles and out-of-pocket maximums

The most common post-payment dispute is a miscalculated deductible. If you've already met your deductible for the year, or your plan has an out-of-pocket maximum you've reached, you shouldn't be billed further. Check the EOB's running totals for the year — insurers show year-to-date progress toward these limits.

The out-of-pocket maximum is the cap on everything you pay in a year — deductible, copays, and coinsurance combined. Once you hit it, your plan pays 100% of covered in-network care, and any bill that ignores that is wrong on its face. If you're close to or past your out-of-pocket max, say so explicitly in your dispute and cite the EOB totals.

Balance billing after insurance

If a provider billed more than your in-network allowed amount, that extra is balance billing. For protected services — emergency care, out-of-network providers at in-network facilities — the No Surprises Act makes it illegal. Send a written dispute citing the protection and the EOB, and file a complaint with your state insurance department if needed.

1. 1Pull the EOB for the service in question.
2. 2Compare the billed balance to the EOB's patient responsibility.
3. 3Check your year-to-date deductible and out-of-pocket totals.
4. 4Write to the billing department citing the discrepancy.
5. 5Invoke No Surprises Act protections for balance-billed services.

If you already overpaid

If you paid the wrong balance, you're owed a refund. Write to the billing department with the EOB, your payment receipt, and the difference you're owed. State law in most places requires refunds for documented over-collection, and your state insurance department will help if the provider stalls.

When insurance underpaid

If the provider's bill is high because your insurer underpaid or denied part of the claim, the dispute belongs with the insurer, not the provider. Appeal the claim with your documentation and ask the provider to hold collection while the appeal proceeds.

Tell the provider in writing that you're appealing the insurance decision and ask them to pause collection activity until the appeal concludes. Providers will usually wait for a claim that's under active appeal — and if they won't, that's a matter for your state insurance department. The same letter to your insurer should request the appeal be handled as expedited if the care is ongoing.