Timely Filing Limits in ABA Billing: When Your Team Has the Wrong Number

Almost every deadline in billing has a way out. Denied for auth, you appeal. Denied for coding, you correct and resubmit. Denied for eligibility, you rebill the right payer.

Timely filing is the exception. Miss that window and the claim is gone. Not disputed, not pending, not worth a phone call. Gone.

Which makes it strange how casually most practices arrive at the number. In one sample ABA audit, a ABA billing team had been working to a 90-day filing limit on a payer that was adjudicating at 60. They'd been doing it for 18 months. Every repeat timely filing denial on that payer traced back to that one wrong assumption, and nobody had gone back to check the source.

Why timely filing limits are worth getting exactly right

The filing clock starts at the date of service and runs regardless of what's happening on your end.

It doesn't pause because the session note wasn't signed. It doesn't pause because a credentialing application is still pending, or because your billing team is short-staffed, or because the claim is sitting in a hold queue that nobody reviews.

Sessions accumulate at their own pace. The clock runs at its own pace. When those two get out of sync, the gap between them is pure write-off.

Here's the part that makes a wrong number expensive rather than just inconvenient. Filing limits vary enormously across ABA payers. Some allow 365 days. Plenty allow 180. Some allow 90. A few allow 60.

That spread means a team operating on one assumed number across all payers will be right for some of them and wrong for the rest, and the wrong ones won't announce themselves until claims start bouncing.

Where ABA teams get the wrong timely filing limits

Four sources, and three of them feel completely reasonable at the time.

A phone rep said so. This is the most common one. Somebody calls, asks, writes it down, and it becomes fact.

In the sample audit, a rep stated 90 days from date of service on 06/23. A different rep at the same payer said 60 days seven days later. Both statements went into the file. The team had already built their process around the first one.

Phone reps are not a reliable source for contractual terms. They're reading the same screens you have access to, often for a different plan than the one your claim falls under.

The provider manual is out of date. Manuals get revised. The PDF saved on your shared drive in 2023 may not describe the current contract, and payers rarely make a point of telling you when a window shortens.

It was inherited. A previous biller set the submission calendar. A new person took over and kept it. Nobody documented where the numbers originally came from, so nobody knows which ones to question.

One number got applied to everything. A team learns that most of their payers allow 180 days and quietly adopts it as the house standard. Works fine until a 60-day payer joins the mix.

What a wrong timely filing limit actually costs

Two costs, and they compound.

The direct cost is the claims you lose. Straightforward, and usually the smaller number.

The larger cost is that a wrong filing limit produces repeat failures rather than one-off ones. Because the number is baked into your submission process, every claim that flows through that process inherits the same error. You don't lose one claim. You lose a category of claims, month after month, until somebody notices the pattern.

In the sample file, one payer's entire $7,310 balance traced back to a single portal verification failure documented 18 months earlier. Access was never restored, claims kept going out late as a result, and the team kept calling about individual denials instead of fixing the access problem that caused all of them.

There's a third cost that's easy to miss: wasted appeal effort. That same file contained an appeal mailed 88 days after the team's own stated 180-day window had already closed. Somebody spent hours assembling medical records and mailing a package that was dead on arrival. The note describing it read confidently. The math didn't work.

Chasing expired claims doesn't just fail. It consumes the hours you needed for the live ones.

Timely filing limits are not the same as appeal windows

Worth separating, because conflating them causes real problems.

The timely filing limit is your window to submit an original claim, measured from date of service.

The appeal window is your window to dispute a decision, measured from the date of the denial or remittance advice.

They're different clocks with different start dates and usually different lengths. A payer might allow 180 days to file and 90 days to appeal, and the appeal clock doesn't start until they've denied something.

A related trap: one appeal cannot cover multiple dates of service with different denial dates. Each claim has its own clock. In that sample file, a single appeal had been submitted covering six dates of service with six separate denial dates, which meant most of it was outside the window before it was mailed.

Also read about https://www.sparkzaba.com/post/what-is-an-aba-ar-audit

How to verify your timely filing limits properly

Five steps, and the first one is the one people skip.

Get it in writing from provider relations, not from a phone rep. Email is fine. What matters is that you have a written statement you can point to, from someone whose job is contract terms rather than claim status.

Verify per plan, not per payer. A payer's commercial plan and their Medicaid managed care plan often carry different windows. So do different state contracts under the same national brand. Ask specifically about the plans your clients are actually on.

Confirm the start date. Date of service is standard, but not universal. Some payers measure from the end of the treatment month. For secondary claims, the clock frequently starts from the primary payer's remittance date, not the original DOS.

Check what the payer is actually doing. This is the check that caught the problem in the sample audit. Pull your timely filing denials from the last six months and calculate the elapsed days between DOS and submission on each one. If claims are bouncing at day 65 on a payer you believe allows 90, the contract on your shelf and the behavior in your remits disagree, and the remits win.

Build to the shortest verified window. Until you've confirmed otherwise per payer, run your submission calendar on the tightest number in your mix. Being early costs nothing. Being late costs the claim.

How SparkzABA finds timely filing problems in your ABA revenue cycle management

The manual version of that fourth check takes a few hours per payer, which is why most practices never run it.

SparkzABA runs it as part of its AR audit. Every open dollar in the file carries the filing or appeal deadline for its specific payer and date of service, and balances whose window closes inside the next 30 days get counted as probable write-offs rather than receivable. That distinction changes the number you're looking at, because AR that can't legally be collected shouldn't be sitting in your receivable total inflating it.

The audit also cross-checks your team's stated filing rules against the payer's actual adjudication behavior. That's how the 60 versus 90 day gap surfaced in the sample file. Two reps had quoted different numbers a week apart, and the payer had denied two claims at exactly the shorter one three days later. All three facts were sitting in the same export. Nobody had put them next to each other.

Same check caught the 88-day-late appeal. The team's own note stated a 180-day rule, the denial dates were in the file, and the appeal date was in the file. The contradiction was arithmetic, and it had gone unnoticed for months because nothing in a standard report compares those three fields.

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Common questions about timely filing limits in ABA billing

Can a timely filing denial be appealed?

Sometimes, but the grounds are narrow. You generally need proof of timely submission, such as a clearinghouse acceptance report showing the original claim went out inside the window, or documentation of a payer-side error like a portal outage or an eligibility record that was wrong at the time. "We were short-staffed" is not appealable. Get your clearinghouse acceptance reports before you write anything.

What is a typical timely filing limit for ABA services?

There isn't a typical one, which is the problem. ABA payers range from 60 days to 365, and the same national payer can carry different windows across states and plan types. Verify per plan rather than assuming a standard, and treat any single number applied across your whole payer mix as a risk.

How do I know if my team has the wrong filing limit?

Pull six months of timely filing denials and calculate elapsed days between date of service and submission for each. If claims are being denied well inside the window you believe you have, your working number is wrong. This check takes an afternoon manually, and it's included automatically in a SparkzABA AR audit.

The one number to verify this week

Pick your highest-volume payer and find out, in writing, what your filing window actually is.

Then pull your last six months of timely filing denials on that payer and check whether the denials line up with the number you were just given. If they don't, you've found a process error that's been quietly running for however long that assumption has been in place.

One payer, one afternoon. It's the cheapest fix in ABA revenue cycle management and it's the one nobody gets around to.