Medical billing mistakes don’t always announce themselves with a denial. Some of them run quietly for months, adding up claim by claim, until someone pulls a report and finds a five-figure hole in collections.
Here are three real patterns, with the math on what each one costs.
Mistake 1: The Wrong CPT Code, Billed on Every Claim
A family practice with two providers. Their biller had been coding established patient visits as 99213 for over a year. The actual level of service for most of those visits was 99214.
The difference in reimbursement between 99213 and 99214 is roughly $30 to $45 per visit depending on payer. The practice sees 40 established patients per day across both providers.
That’s a $1,200 to $1,800 daily underpayment. Over 12 months, the underbilling totaled more than $300,000 in lost revenue.
The biller wasn’t committing fraud. She was being conservative. She’d been trained to code low to avoid audits. Nobody told her the documentation supported a higher level of service. No one was reviewing the data to catch the pattern.
This is one of the most common billing mistakes in primary care. It’s invisible until someone looks at the numbers by CPT code.
Mistake 2: Missing the Modifier
A two-physician OB/GYN practice. Their biller was submitting same-day preventive and problem visit claims without Modifier 25 on the E/M component.
Modifier 25 tells the payer that the E/M service was significant and separately identifiable from the preventive visit. Without it, most payers bundle the E/M into the preventive payment and deny the E/M separately.
The practice had approximately 15 of these same-day visits per week. Each E/M was worth $90 to $140. Without the modifier, none of them paid.
Over six months, the total uncollected revenue from missing Modifier 25 alone was $28,000 to $40,000. The fix was two minutes of training and a workflow update. The damage took six months to accumulate.
Mistake 3: Ignoring the Clearinghouse Rejection Queue
A behavioral health group running eClinicalWorks. Their biller was submitting claims daily, but wasn’t checking the clearinghouse rejection queue consistently. Claims that rejected at the clearinghouse never reached the payer. The practice had no idea.
Over 90 days, 143 claims had rejected and were never resubmitted. The average value per claim was $185. Total uncollected: $26,455. Several of those claims were past the timely filing window by the time someone caught the issue. That revenue was gone permanently.
Clearinghouse rejections don’t always show up as denials in the EHR. They show up in the clearinghouse portal, which requires a separate login. Billers who aren’t checking that queue daily are flying blind on a significant percentage of their submissions.
The Common Thread
All three of these mistakes share one characteristic. No one was reviewing the data.
A biller who is submitting claims but not reviewing reports is only doing half the job. The submission is the easy part. The analysis, the pattern recognition, the daily denial work and weekly performance review, that’s what separates billing that collects 97 percent of allowable from billing that collects 88 percent.
For a $2M revenue practice, the difference between 88 percent and 97 percent collection rate is $180,000 per year.
What a Billing Audit Finds
When we take on a new client at Dr. Billerz, we start with a billing audit before anything else. In the first review, we consistently find:
- CPT code distribution that suggests systematic undercoding
- Modifier patterns that indicate missed revenue on same-day services
- Clearinghouse rejection queues with unworked items
- 90-day AR buckets with claims that are still within the appeal window
- Payers who are consistently underpaying contracted rates without challenge
The audit is included in the 4-week free pilot. You find out exactly what’s happening in your billing before you commit to anything.
Book a 15-minute call to talk through what an audit would cover for your practice specifically.
Frequently Asked Questions
How do I know if my practice is undercoding E/M visits?
Pull a CPT code distribution report from your EHR. Look at the ratio of 99213 to 99214 for established patients. For a mixed adult primary care practice, you’d typically expect to see more 99214 than 99213. A heavy skew toward 99213 on a complex patient panel is a red flag for undercoding.
Is undercoding a compliance risk?
Systematic undercoding is generally not a compliance risk in the way overcoding is, but it is a significant revenue risk. More practically, if a payer audit finds you were consistently billing lower than the documentation supports, there’s no recoupment, but there’s also no retroactive payment for what you undersold.
Can you recover claims that were rejected at the clearinghouse months ago?
Yes, if they’re within the timely filing window. Clearinghouse rejections are not payer denials. They never reached the payer. As long as you resubmit before the timely filing deadline, the claim is treated as a new submission.
How often should someone be reviewing billing performance reports?
Denial queue: daily. AR aging: weekly. Clean claim rate and collection rate by payer: monthly. CPT distribution and modifier patterns: quarterly. Most practices do none of these consistently. That’s why billing problems compound quietly over months before someone notices.