Laboratory Billing Services

Laboratory billing is a high-volume, low-margin business. A single day can bring hundreds of orders, each tied to a test code, a diagnosis, and a payer rule. One missing diagnosis or a wrong code can hold up a claim that is worth little on its own, and those small losses add up.

Labs also face rules that many practices never see. Medicare payment for clinical lab tests follows a national fee schedule, and its rates and reporting rules have changed under the Protecting Access to Medicare Act (PAMA) with several delays from Congress. CLIA certification (the federal lab quality program) controls which tests a site may run and bill. Westmont connects clinical and reference labs with vetted billing experts who understand these demands.

Who this is for

• Independent clinical and reference laboratories
• Hospital outreach labs
• Physician office labs holding a CLIA certificate
• Specialty and esoteric testing labs
• Start-up labs setting up payer enrollment
• Labs that bill client practices, patients, and insurers

What gets billed

• Blood counts and chemistry panels
• Lipid and diabetes monitoring tests
• Thyroid and hormone tests
• Urinalysis and urine cultures
• Microbiology cultures and infectious disease molecular tests
• Coagulation tests
• Specimen collection and venipuncture
• Reference lab send-out testing
• Point-of-care tests run under a CLIA waiver
• Respiratory and sexually transmitted infection panels

Commonly billed codes

Code	Type	What it covers
85025	CPT	Complete blood count with automated differential
80053	CPT	Comprehensive metabolic panel
80048	CPT	Basic metabolic panel
80061	CPT	Lipid panel
83036	CPT	Hemoglobin A1c, a blood sugar average over time
84443	CPT	Thyroid stimulating hormone test
81001	CPT	Automated urinalysis with microscopy
87086	CPT	Urine culture with colony count
87635	CPT	Test for the virus that causes COVID-19, using amplified probe
36415	CPT	Collecting blood by venipuncture
E11.9	ICD-10-CM	Type 2 diabetes without complications
E78.5	ICD-10-CM	High cholesterol or lipids, unspecified

Note

Codes are examples for orientation, not a complete list, and do not guarantee coverage or payment. Always check current code sets and payer policy.

Billing challenges in laboratory services

• Medical necessity. Many tests are covered only for certain diagnoses. Medicare uses national and local coverage policies to set these. A lab biller checks each policy and builds order edits so missing or weak diagnoses are caught early.
• Panel unbundling. Billing individual tests that belong in a panel can trigger denials or audits. Billers apply panel rules and review code edits before claims go out.
• CLIA certificate type. A lab may bill only for tests allowed under its certificate. Waived tests often need modifier QW. Billers confirm certificate details on file with each payer.
• Order and requisition quality. Missing patient data, ordering provider details, or diagnoses stop claims. Billers work with client offices to fix intake problems at the source.
• Frequency limits. Payers may cap how often a test can be paid. Billers track patient history where they can and use advance beneficiary notices when needed and allowed.
• Payment rate changes. Medicare lab rates and PAMA reporting timelines have shifted more than once. Check CMS for current-year information, and have billers model the impact on your test mix.
• Client billing versus insurance billing. Some states limit how a lab may bill a client practice. Billers set up payer paths that match state rules and your contracts.

How Westmont can help

• Match your lab with vetted billing experts experienced in clinical and reference testing
• Support end-to-end revenue cycle work, from order intake to posting
• Help with denial management, appeals, and trend reporting by test and payer
• Assist with payer enrollment and credentialing for new and growing labs
• Review how your lab handles client billing, patient statements, and write-offs

Frequently asked questions

What does a clinical laboratory billing company do?

It turns lab orders into clean claims. That includes checking patient and provider data, matching tests to diagnoses, applying panel and frequency rules, submitting claims, posting payments, and working denials. Some also help with patient statements and client invoicing. Ask any billing partner how it handles each step for your volume.

What is the QW modifier?

QW tells payers that a test was run under a CLIA certificate of waiver. Many waived tests need it on the claim for Medicare, though not every waived test does. Payers differ, so check each payer's policy. Missing or misused modifiers are a common cause of lab denials.

How does PAMA affect lab billing?

PAMA ties Medicare lab payment to private payer rates reported by labs. Timing of reporting and rate changes has been adjusted by Congress more than once. Check current CMS and lab association updates, because the rules can change from year to year.

Why do lab claims get denied for medical necessity?

The diagnosis on the order may not match what the payer covers for that test. Sometimes the diagnosis is missing or too general. Labs can reduce these denials with order forms that capture specific diagnoses and by educating client offices on documentation.

Can we bill for tests we send to a reference lab?

Rules depend on the payer, the state, and the type of arrangement. Some payers require the performing lab to bill directly. Review your contracts and payer policies, and ask a billing expert to confirm the correct method.

Related billing services

• Pathology Billing
• Toxicology Lab Billing
• Genetics Billing
• Mobile Diagnostic Billing
• Hospital Billing
• Ambulatory Billing