What is Accounts Receivable in medical billing, and why is AR aging important?

In medical billing, Accounts Receivable (AR) refers to money that is still owed to the healthcare provider after services have been rendered and claims or patient balances have been created.

AR may include:

• Insurance balances awaiting payment
• Denied or underpaid claims
• Claims pending additional information
• Patient responsibility balances
• Secondary insurance balances
• Claims requiring follow-up, appeal, or correction

The purpose of AR follow-up is to identify why an outstanding balance has not been resolved and take the appropriate action to move the account toward payment or another valid resolution.

AR aging is the process of grouping outstanding balances according to how long they have remained unpaid. Common aging buckets include:

• 0–30 days
• 31–60 days
• 61–90 days
• 91–120 days
• More than 120 days

The exact aging structure can vary by organization, but the purpose is the same: to show how old the outstanding receivables are.

AR aging is important because older balances generally become more difficult to collect. As claims age, the billing team may face risks such as timely filing limits, appeal deadlines, missing documentation, payer follow-up delays, or difficulty obtaining information needed to resolve the account.

A good AR process does not simply work the oldest claim first. The team should consider several factors, including:

• Claim age
• Outstanding balance
• Payer filing or appeal deadlines
• Denial reason
• Claim status
• Previous follow-up
• Expected reimbursement
• Whether action is required from the payer, provider, patient, or another department

For example, a 45-day-old claim with an appeal deadline approaching may require more urgent attention than a 100-day-old claim that is already processing correctly with the payer.

AR aging also helps management evaluate the financial health and operational performance of the revenue cycle. A high percentage of balances in older aging buckets can indicate problems such as unresolved denials, weak follow-up, eligibility errors, authorization issues, payment posting delays, or payer-related processing problems.

Effective AR management focuses on resolving claims as early as possible and preventing balances from unnecessarily moving into older aging buckets

A billing team reviews its AR report and finds three outstanding claims:

• Claim A is 25 days old and is still processing normally.
• Claim B is 65 days old and was denied for missing authorization.
• Claim C is 110 days old, but a reconsideration was already submitted and is still within the payer’s review timeframe.

The AR representative should not automatically work Claim C first simply because it is the oldest.

Claim B may require immediate attention if there is a limited appeal or reconsideration deadline, while Claim C may only require monitoring until the payer’s stated processing timeframe has passed.

This demonstrates why AR aging should be used together with claim status and payer requirements.