Pathology & Laboratory Billing Services

Laboratory billing is a volume business with a precision problem. A single requisition can generate dozens of tests, each with its own code, its own diagnosis link, and its own payer coverage rule, and a lab can run thousands of claims a day. The denials that hurt most are systematic: a panel unbundled into its components, a test billed without a supporting diagnosis, or a modifier missing on a reference lab claim, repeated across every claim in a batch until someone notices.
MedPlus RCM provides medical billing, coding, credentialing, and denial management for pathology and laboratory services, built around panel rules, medical necessity linkage, and the modifiers that keep high volume lab claims clean.

Pathology & Laboratory billing challenges

Most laboratory tests fall in the CPT Pathology and Laboratory section, codes 80047 through 89398, plus proprietary laboratory analyses codes that end in U. The section covers panels, drug testing, urinalysis, molecular pathology, chemistry, hematology, immunology, microbiology, cytopathology, cytogenetics, and surgical pathology. Common examples include the basic metabolic panel (80048), comprehensive metabolic panel (80053), lipid panel (80061), CBC with differential (85025), hemoglobin A1c (83036), and surgical pathology examinations (88305 for level IV and 88307 for level V), with immunohistochemistry billed per antibody (88342). Venipuncture (36415) sits outside the section, in Surgery.
Panel integrity is the first rule. When all components of a panel are performed, the panel code must be reported rather than the individual component tests, and unbundling a panel into its parts triggers a bundling denial. Repeat testing on the same day is handled with modifier 91 for a repeat clinical diagnostic laboratory test, not by defaulting to a distinct service modifier. Reference laboratory work uses modifier 90, CLIA waived tests use modifier QW with the CLIA number in the correct claim field, and pathology services split into professional and technical components use modifiers 26 and TC, just as in radiology.
Medical necessity is the second rule, and it is enforced test by test. Every lab claim needs the ordering provider’s diagnosis, coded to the highest specificity, that matches the payer’s covered list for that test. For Medicare, that list comes from a national or local coverage determination and its billing and coding article. A test billed with no supporting indication, with a screening code where a diagnostic code was needed, or with a diagnosis that does not justify the test will deny for medical necessity. When coverage is doubtful, a signed advance beneficiary notice collected before the specimen protects the lab. Medicare pays most laboratory services through the Clinical Laboratory Fee Schedule, a national rate table updated annually, so rates shift year to year and last year’s payment cannot be assumed for this year’s tests. Medically unlikely edits also cap the units of service per day for many tests, and splitting tests across days to avoid those limits is a compliance risk.

What MedPlus RCM handles for pathology & laboratory practices

  • End-to-end medical billing. Charge entry, claim scrubbing, submission, payment posting, and patient billing, the full cycle.
  • Medical coding. Certified coders assign current ICD-10, CPT, and HCPCS codes matched to your documentation and specialty.
  • Provider credentialing and enrollment. End-to-end enrollment with commercial payers and Medicare, plus re-credentialing maintenance.
  • Denial management and recovery. Every denial investigated to root cause, corrected, and appealed with documentation.
  • A/R recovery. Aged and outstanding balances audited and pursued, including balances already written off where the appeal window is still open.
  • Financial reporting. Clean claim rates, collections, denial patterns, and A/R aging visible by payer and provider.
    We serve pathology and laboratory practices nationwide, including independent labs, hospital labs, and pathology groups, across clinical chemistry, hematology, microbiology, molecular diagnostics, cytopathology, and surgical pathology.

Results pathology & laboratory practices can check

MedPlus RCM maintains a 99% clean claim rate and keeps client accounts receivable under 30 days. Pricing is a performance-based percentage of successfully collected revenue: if you don’t get paid, we don’t get paid. We are 100% HIPAA compliant, and onboarding takes 2 to 4 weeks depending on practice size, with no disruption to your daily cash flow.

Frequently asked questions

Why do lab claims deny for medical necessity?
Because the diagnosis on the claim does not support the test ordered, the diagnosis lacks specificity, or a screening code was used where a diagnostic code was needed. The ordering provider’s diagnosis must match the payer’s covered list for that test.
Should we bill panel components separately?
No. When all components of a panel are performed, report the panel code. Billing the individual tests instead triggers a bundling denial.
What modifiers do labs use most often?
Modifier 90 for reference lab tests, 91 for same day repeat tests, QW for CLIA waived tests, 26 and TC for split pathology billing, and 59 or an X modifier for genuinely distinct services. Each requires documentation to support it.
How does Medicare pay for lab tests?
Mostly through the Clinical Laboratory Fee Schedule, a national rate table that CMS updates annually. Rates change year to year, so fee schedule updates should be checked rather than assumed.
What protects the lab when coverage is doubtful?
A signed advance beneficiary notice collected before the specimen is taken, which documents that the patient was informed the test might not be covered.

Get a free financial audit

Find out where your pathology or laboratory practice is losing revenue. Request a free financial audit and our specialists will review your claims, denials, and A/R.
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