Medicare timely filing limits are a constant thorn in the side of medical billers. Get them wrong, and you’re looking at CO 29 denials — “The time limit for filing has expired.” These denials aren’t just frustrating. They can mean the difference between getting paid and writing off a claim entirely. Knowing the deadlines for Medicare Part A, Part B, Medicare Advantage, and secondary claims can save you a lot of headaches.
Medicare Part A: Hospital Insurance
For Medicare Part A, which covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health care, the timely filing limit is traditionally one year from the date of service. But there’s a catch. The deadlines are often based on the end of the calendar year. This means if a service was provided on March 15, 2023, you have until December 31, 2024, to file the claim.
But don't let this lull you into complacency. If your claim spans different dates of service, each date could potentially have a different filing deadline. Staying organized is key. Use software alerts or good old-fashioned spreadsheets to keep track of these dates.
Medicare Part B: Medical Insurance
Medicare Part B covers outpatient services — think doctor visits, outpatient care, medical supplies, and preventive services. Much like Part A, the general timely filing limit is one year from the date of service. However, always double-check the exact date using the end-of-year calculation method. A clinic visit on February 10, 2023, means you must file by December 31, 2024.
Here's a tip: Don’t wait until the year is almost up. Payers are notorious for dragging their feet when it’s crunch time. Avoid being on hold with Medicare for hours in early December because everyone else waited too.
Medicare Advantage: Part C Plans
This is where it gets tricky. Medicare Advantage (Part C) plans are administered by private insurers, not the government. Each insurer sets its own timely filing limits, which means you could be looking at anywhere from 90 days to a full year from the date of service.
Humana, for instance, typically requires claims within 365 days, while UnitedHealthcare might give you only 90 days. And these limits can change with little notice. Always verify with the specific plan — and make it a habit to do so regularly.
Secondary Claims: When Medicare Pays First
Secondary claims often slip through the cracks. Medicare as a primary payer follows the standard Part A and Part B timely filing limits. But when submitting a secondary claim to another payer, those deadlines can be dramatically different.
Say your patient has a secondary payer that allows 180 days from the date of Medicare’s payment. If Medicare paid on March 1, 2023, you’ve got until August 28, 2023, to file the secondary claim. That’s just six months — a deadline many billers miss because they’re focused on the primary claim.
Avoiding the Dreaded CO 29 Denial
CO 29 denials are non-negotiable. Get a denial due to untimely filing, and you’re out of luck — unless you have a very good reason, like a natural disaster delay. (Good luck arguing a slow internet day.)
To avoid these denials, implement a tight claim management process. Log every claim date, set reminders well before deadlines, and double-check payer guidelines. And if you ever find yourself with a CO 29 denial without a plausible excuse, consider it a learning opportunity to tighten your process.
Tools and Strategies
Use technology to your advantage. Claims management software that tracks deadlines can save hours of manual monitoring. These platforms often alert you to upcoming deadlines, reducing the risk of an expensive oversight.
Additionally, communicate with your team. Regularly discuss deadline policies and insurer changes. Make sure everyone is aware of the importance of timely filing — and the consequences of missing a deadline.
Final Thoughts
Timely filing is your responsibility. It’s not the payer’s job to remind you or make exceptions. And while it might feel like another tedious rule to follow, it’s one of the most important. Getting your claims in on time is the difference between a smooth revenue cycle and the chaos of denied claims. Don't let CO 29 denials be a regular part of your billing process. Stay vigilant, stay informed, and keep those deadlines front and center.
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