The ABN Trap: How Labs Use a Medicare Form to Charge You 5× What Tests Are Worth

If you’ve had lab work done on Medicare, there’s a good chance you’ve signed a form called an Advance Beneficiary Notice — an ABN. You probably signed it quickly in a stack of paperwork before your blood draw. Most people do.

That signature may be the most expensive thing you write all year.

What the ABN actually does

An ABN (officially Form CMS-R-131) is a notice labs are required to give you when they believe Medicare might not cover a test. The form is a CMS (Centers for Medicare & Medicaid Services) requirement. By signing it, you agree to pay whatever the lab charges if Medicare says no. In theory it exists to give you a choice: accept the test and the financial risk, or decline it.

In practice, it’s handed to you in a clinical setting, often with little explanation, right before your blood is drawn. In my own recent case, I was already in the chair seconds away from the needle and had to select options on a computer screen and sign electronically — with no time to read carefully, think, or discuss. I did ask about the Medicare rate and the tech said she had no idea. The choice doesn’t feel like a choice.

What they don’t tell you

Here’s what’s missing from that moment: any context for what “whatever the lab charges” actually means. Labs set their own prices, and those prices often have almost no relationship to what Medicare — or any insurer — considers reasonable.

Medicare publishes a Clinical Laboratory Fee Schedule that sets payment rates for thousands of tests. These rates are based on what private insurers actually pay, updated under the Protecting Access to Medicare Act. They represent a real-world market price.

Lab “list prices” — what they put on your bill — are typically 3 to 6 times higher than those rates. On my own ABN this year, six tests carried a lab estimate of $1,068.32. Medicare’s rate for those same tests? $96.91. That’s an 11× markup.

The ABN doesn’t give you this context. CMS requires labs to include an estimated cost on the form, but even when they fill it in, the number reflects the lab’s inflated price — not what the test is worth in any real market.

What the experts say

“ABNs must be delivered far enough in advance of providing potentially non-covered items so as to allow the beneficiary an opportunity to consider all available options.”
— Center for Medicare Advocacy

The Center for Medicare Advocacy, a leading nonprofit focused on Medicare beneficiary rights, also notes that if a provider refuses to answer a beneficiary’s questions about an ABN, “the provider will be liable for non-covered care.” The problem is that pushing back requires data most patients don’t have at the counter.

What happens if you don’t sign

This is the part most people never hear: if Medicare denies a test as not reasonable and necessary and the lab did not get a valid signed ABN before running it, the lab — not you — is financially responsible. Medicare’s manual says the provider “is precluded from collecting funds from the beneficiary and is required to make prompt refunds if funds were previously collected” (Medicare Claims Processing Manual, Pub. 100-04, Ch. 30 §50.9.B; 42 CFR §411.404). On your Medicare Summary Notice, that kind of denial may read “The information provided does not support the need for this service or item.” The claim gets coded with modifier GZ instead of GA, and the lab eats the cost.

This does not apply to services Medicare never covers, such as labs ordered only as part of a routine physical checkup (Social Security Act §1862(a)(7)). Your MSN may say “Routine examinations and related services aren’t covered.” You owe those even without an ABN.

That’s why your signature matters so much to them. And why it should matter to you.

Your three choices on every ABN

Option 1 — The lab bills Medicare and bills you only if Medicare denies. You keep your right to appeal. If Medicare pays, you owe nothing.
Option 2 — You pay now. Medicare is never billed. You lose all appeal rights.
Option 3 — The test isn’t performed. You owe nothing and can take the time to talk to your doctor about whether a different diagnosis code or a different lab would change the outcome.

What you can do — starting before you sign

You don’t have to sign blind. Before you pick up that pen, run a Pre-Check on your order right there in the provider’s office. In about 60 seconds you’ll see what Medicare actually pays for every test listed — and whether your diagnosis codes match Medicare’s accepted list. You can show those numbers to the person handing you the form.

If your diagnosis codes don’t match Medicare’s accepted list for the tests being ordered, ask your doctor to revise before the lab visit. That eliminates the ABN in the first place.

A conversation about a $1,068 charge goes very differently when both of you can see that Medicare’s rate is $97.

If you’ve already signed and gotten a bill

You’re not out of options. Two questions to ask:

Was the ABN valid? Did the lab give you the form before the test, explain it clearly, and give you a real chance to decline? If not, the ABN may not be enforceable.
Was the denial correct? Read the denial reason on your Explanation of Benefits (EOB) carefully. Medicare denials can be appealed, and many are overturned, especially when the ordering physician provides supporting documentation. CMS outlines the redetermination process in detail.

Even if both answers are yes, you still have leverage. A lab defending a 1,000% markup has a much harder time when you can show what Medicare pays and what other labs charge for the same test.

GougeStop, a Medterpret tool, checks the bill against Medicare’s rate and walks you through negotiating it if you’ve already been billed.

The ABN isn’t going away. But the information gap it exploits can.

Sources

CMS — Beneficiary Notices Initiative (ABN Form CMS-R-131)
CMS — Clinical Laboratory Fee Schedule
Center for Medicare Advocacy — Advance Beneficiary Notices (ABNs)
CMS — First Level of Appeal: Redetermination by a Medicare Contractor
CMS — How to Read an Explanation of Benefits