Most laboratory owners and clinic managers assume their billing is working fine. Revenue comes in, claims go out, and as long as the lights stay on, the system seems to be doing its job. But in our experience working with labs and physician offices across the country, that assumption is costing practices tens of thousands of dollars every year — sometimes more.
Medical billing for laboratories and clinics is one of the most complex billing environments in healthcare. The rules are specific, the payer requirements vary widely, and the margin for error is razor thin. Here are the most common billing mistakes we see, and what you can do about each one.
Mistake 1: Billing Without Proper Medical Necessity Documentation
This is the single most common reason laboratory claims get denied. Medicare and most commercial payers require that every test ordered has documented medical necessity — meaning the ordering provider's notes must clearly support why that specific test was needed for that specific patient at that specific time.
When documentation is vague, missing, or doesn't align with the diagnosis codes on the claim, the payer denies it. Many labs simply write it off. But these denials are almost always preventable and often recoverable.
What to do: Work with your ordering providers to ensure their clinical notes support every test ordered. Implement a pre-billing review process that checks diagnosis codes against ordered tests before claims go out. If you're getting consistent denials for specific test types, that's a signal to audit your documentation workflow for those tests.
Mistake 2: Using Outdated or Incorrect CPT Codes
CPT codes change every year. New codes are added, old ones are deleted, and existing codes are revised. A code that was correct in 2022 may be bundled, deleted, or replaced in 2024. Billing with outdated codes results in denials, underpayments, and in some cases, compliance risk.
This is especially common in toxicology, molecular testing, and immunology — areas where the coding landscape has shifted significantly over the past several years.
What to do: Conduct an annual CPT code review at the start of each calendar year. Subscribe to AMA CPT code update notifications. If you're billing toxicology or molecular tests, consider working with a billing specialist who focuses on laboratory coding — the nuances are significant and the financial impact of getting it wrong is substantial.
Mistake 3: Missing or Incorrect ABN Management
An Advance Beneficiary Notice of Noncoverage (ABN) is a form that Medicare beneficiaries must sign when there's reason to believe Medicare won't cover a service. If you don't have a properly executed ABN on file and Medicare denies the claim, you cannot bill the patient. You absorb the loss.
Many labs either skip ABNs entirely, use outdated forms, or fail to complete them correctly. A blank ABN with no specific test listed, no estimated cost, and no patient choice selected is not a valid ABN. Medicare will not honor it.
What to do: Implement a systematic ABN workflow for all Medicare patients. Train front-desk and phlebotomy staff on when ABNs are required and how to complete them correctly. Use the current CMS-approved ABN form — the version changes periodically. Keep signed ABNs on file for at least seven years.
Mistake 4: Ignoring Claim Denials Instead of Working Them
The average denial rate across healthcare is around 5–10%. For laboratories, it's often higher. What's worse is that many labs have a denial follow-up rate that's far too low — meaning a significant percentage of denied claims are simply written off without any attempt at recovery.
Every denial has a reason code. Most denial reason codes fall into a handful of categories: missing information, medical necessity, duplicate claim, timely filing, or authorization issues. Each category has a defined resolution path. Working denials is not optional — it's revenue recovery.
What to do: Establish a denial management workflow with defined timelines. Claims should be worked within 30 days of denial. Track denial reasons by payer and by test type — patterns reveal systemic problems that can be fixed upstream. Set a target denial recovery rate and measure against it monthly.
Mistake 5: Failing to Verify Insurance Before Testing
Billing a claim to the wrong payer, billing a patient who has changed insurance, or billing a patient who is no longer covered is one of the most avoidable sources of revenue loss. Yet many labs and clinics still rely on insurance cards that may be months or years out of date.
What to do: Verify insurance eligibility electronically for every patient at every visit — not just new patients. Most practice management systems have real-time eligibility verification built in. If yours doesn't, there are standalone tools that integrate with most systems. The cost of verification is a fraction of the cost of a single uncollectable claim.
Mistake 6: Not Credentialing with All Relevant Payers
If your laboratory or clinic is not credentialed with a payer, you cannot bill that payer for services. Any claims submitted without proper credentialing will be denied, and in many cases you cannot retroactively recover that revenue even after credentialing is complete.
New labs frequently make this mistake by starting to see patients before credentialing is finalized. Existing labs make it when they add new providers or new test types that require separate credentialing.
What to do: Build a credentialing calendar and track expiration dates for all payer contracts. When adding new providers or new services, start the credentialing process at least 90–120 days before you plan to begin billing. Keep copies of all credentialing approvals and contract terms on file.
Mistake 7: Underutilizing Modifier Codes
Modifier codes provide additional context about a service that affects how it's billed and reimbursed. In laboratory billing, modifiers are used to indicate things like repeat testing, multiple specimens, reduced services, and more. Using the wrong modifier — or failing to use one when required — can result in denials, underpayments, or compliance issues.
What to do: Ensure your billing team is trained on the modifier codes most relevant to your test menu. Conduct periodic audits of claims to verify that modifiers are being applied correctly and consistently.
Mistake 8: Not Tracking Key Billing Metrics
You cannot improve what you don't measure. Many labs and clinics have no visibility into their billing performance beyond total collections. They don't know their denial rate, their days in accounts receivable, their clean claim rate, or their collection rate by payer. Without these metrics, billing problems are invisible until they become crises.
What to do: Establish a monthly billing dashboard that tracks at minimum: denial rate, days in AR, clean claim rate, collection rate by payer, and write-off rate. Review these metrics with your billing team monthly and set improvement targets. If you don't have the internal capacity to track these, that's a sign you may need outside support.
The Bigger Picture
Billing errors don't just cost money. They create compliance risk, damage payer relationships, and consume staff time that could be spent on patient care. The labs and clinics that consistently maximize revenue are the ones that treat billing as a strategic function, not an administrative afterthought.
At Hope Consultation, we specialize in revenue cycle management for laboratories and physician offices. Through our HopeRCM platform, we combine AI-powered billing technology with hands-on consulting expertise to identify exactly where your revenue is leaking and fix it — systematically.
If you're not sure whether your billing is performing at its potential, the first step is a billing audit. We'll review your claims data, denial patterns, and collection rates and give you a clear picture of where you stand and what's possible.
Contact us to schedule a free consultation. There's no obligation — just an honest conversation about your revenue cycle and how to make it stronger.
