Pathology Billing Services for Groups

Pathology Codes We Bill Most

Modifiers That Matter

Payer Rules to Know

Top Denials in Pathology Billing Services for Groups

What Does Pathology Billing Cover?

Pathology billing covers two kinds of work: anatomic pathology, where a pathologist examines tissue and cells and signs a diagnosis, and clinical pathology, where a laboratory runs tests on blood, urine and other fluids. This page covers the physician side: surgical pathology, cytology, immunohistochemistry (IHC, a stain that uses antibodies to show what a cell is made of), special stains, frozen sections and consultations.

Under 42 CFR 415.130(b), Medicare pays physician pathology on the fee schedule for surgical pathology, specific cytopathology, hematology and blood banking services that need a physician, qualifying clinical consultations and listed laboratory interpretations. Routine lab testing falls under the clinical laboratory fee schedule, covered on the separate laboratory billing page. Hematology interpretation belongs to hematology billing.

The claim is usually a CMS-1500, the professional claim form. A group bills either the whole service or only the interpretation, depending on who owns the lab and where the patient was.

What Is the Difference Between Global, 26 and TC in Pathology Billing?

The global service is the whole test: preparing the slide and interpreting it. Modifier 26 marks the professional component, which is the pathologist's work. Modifier TC marks the technical component, which is the lab's staff, equipment and supplies. See modifier 26 and modifier TC.

Whether a code can be split at all is set by the PCTC indicator in the CMS Physician Fee Schedule relative value file. In the October 2026 release (RVU26D), the codes 88300, 88305, 88307, 88312, 88313, 88331, 88342, 88341, 88344, 88360, 88361 and G0452 all carry indicator 1, which means modifiers 26 and TC apply. Code 88141 carries indicator 2, a professional-only code, so 26 and TC cannot be added to it.

CMS states the rule in the file layout: for indicator 1 codes, the total relative value units for a code with modifier 26 include physician work, practice expense and malpractice expense, while a code with modifier TC includes practice expense and malpractice expense only.

When Can a Pathology Group Bill the Technical Component?

It depends on where the specimen came from. Medicare does not pay the physician fee schedule for the technical component of a pathology service when the patient is in a hospital inpatient or outpatient setting, because that component is bundled into the hospital's payment. The Medicare Claims Processing Manual, Chapter 12, section 60, says so directly.

An independent laboratory can still bill the technical component for non-hospital patients and where it is not bundled into a facility payment, such as an ambulatory surgery center. For hospital patients, the professional component stays billable by the hospital's physicians or by an independent lab that qualifies as the reassignee.

What Happened to the Grandfathered Hospital Arrangements?

They ended. Under 42 CFR 415.130(d)(2), for services furnished after June 30, 2012, an independent laboratory may not bill the Medicare contractor for the technical component of physician pathology services furnished to a hospital inpatient or outpatient. Before that date, a lab could bill if the hospital had an arrangement with it in effect on July 22, 1999. The Claims Processing Manual, Chapter 12, section 60.B.2, repeats the July 1, 2012 end date.

If you do the technical work for a hospital, the hospital is paid through its own claim and settles with you under your arrangement. That is client billing, covered below.

• Hospital patient, group reads the slide: bill the professional component (26) to the payer.
• Hospital patient, group's lab prepared the slide: bill the hospital under your contract.
• Non-hospital patient, group's lab prepared and read the slide: bill the global service.
• Non-hospital patient, lab prepared the slide and a separate group read it: lab bills TC, reading group bills 26.

How Many Units of 88305 Can We Bill for Multiple Specimens?

Bill one unit of 88305 for each specimen. Chapter X of the 2026 NCCI Policy Manual (revision date January 1, 2026) says the unit of service for surgical pathology codes 88300 to 88309 is the specimen, and defines a specimen as tissue submitted for individual and separate attention, examination and diagnosis. NCCI is the National Correct Coding Initiative, the CMS edit program that sets these limits.

Separate specimens are usually in separate containers, and it must be medically reasonable and necessary to examine them separately. The manual's example is two polyps at 15 cm and 25 cm in a colonoscopy, which may be separate specimens. Multiple biopsies of the same polyp are usually one specimen. See the 88305 page.

Payers add their own wording. UnitedHealthcare commercial policy 2026R0010C says duplicate pathology specimens reported with the same surgical pathology code must carry modifier 59, XE, XP, XS, XU or 91 to receive separate consideration,, and says specimens from the same anatomic site with the same code may be reported on one line with multiple units.

Prostate Needle Biopsies Are Not Billed as 88305

CMS requires surgical pathology for all prostate needle biopsy specimens from one patient to be reported as one unit of HCPCS G0416, not 88305 (NCCI Policy Manual, Chapter X). UnitedHealthcare states the same and says 88305 will not be reimbursed for prostate needle biopsy surgical pathology. G0416 is a one-unit code no matter how many cores or containers there are.

How Do We Bill 88342 and Immunohistochemistry Stains?

Bill 88342 once for the first antibody stain on a specimen, then 88341 for each additional single antibody stain on that same specimen. The NCCI Policy Manual, Chapter X, says the unit of service for 88342, 88341 and 88344 is each single or multiplex antibody stain procedure per specimen. See the 88342 page.

Three details drive IHC units. A stain run on several blocks of one surgical specimen counts as one unit for that specimen. An antibody cocktail without separately interpretable results is one unit. A true multiplex stain, where each antibody gives its own reportable result, is 88344, one unit per procedure per specimen.

Medicare does not pay twice for the same answer. The manual says IHC (88342, 88341, 88344, 88360, 88361) and flow cytometry (88184 to 88189) should generally not be reported for the same or similar specimens, and that when both methods are truly needed, modifier 59 or XU and documentation of the reason are required.

Quantitative tumor IHC by manual technique is 88360, and with computer-assisted analysis it is 88361. Results graded 1+ to 4+ stay in the 88342, 88341 and 88344 family. Special stains (88312 and 88313) count once per stain per block, so extra levels cut from one block add no units.

What Is the 14-Day Date of Service Rule for Pathology Specimens?

The date of service for the technical component of a pathology service is normally the date the specimen was collected. 42 CFR 414.510(a) says so, and the same rule covers clinical laboratory tests. If collection spans two calendar days, the date of service is the day collection ended.

The 14-day rule is an exception for stored specimens. Under 42 CFR 414.510(b)(2)(i), when a specimen was stored 30 calendar days or fewer, the date of service is the date the test was performed, but only if all of these are true:

• The patient's physician ordered the test at least 14 days after the patient's discharge from the hospital.
• The specimen was collected during a hospital surgical procedure.
• It would have been medically inappropriate to collect the sample at any other time than the procedure that led to the admission.
• The results do not guide treatment during the hospital stay.
• The test was reasonable and medically necessary for treating an illness.

If the specimen sat for more than 30 calendar days, it is treated as archived, and the date of service is the date it was taken out of storage (42 CFR 414.510(b)(2)(ii)). Chemotherapy sensitivity tests on live tissue have a parallel exception in paragraph (b)(3), and molecular pathology tests have one in paragraph (b)(5).

Chapter 16, section 40.8 of the Claims Processing Manual restates the policy. For a routine biopsy, none of the exceptions apply and the collection date is the date on the claim.

Does a Pathology Group Need CLIA, and What Must Be on File?

Yes, if the group runs a laboratory that tests human specimens. 42 CFR 493.3(a) says a laboratory will be cited as out of compliance unless it holds a current certificate applicable to the category of tests it performs, or is CLIA-exempt. CLIA, the Clinical Laboratory Improvement Amendments, sorts tests into waived, moderate complexity and high complexity under 42 CFR 493.5.

The number reaches the claim on the CMS-1500. Chapter 26 of the Claims Processing Manual says to enter the 10-digit CLIA certification number in item 23 for laboratory services billed by an entity performing CLIA-covered procedures.

42 CFR 493.1105 requires pathology test reports to be kept at least 10 years from the date of reporting, histopathology slides at least 10 years from the date of examination, cytology slides at least 5 years, and pathology specimen blocks at least 2 years.

How Do We Bill Client Versus Patient for Anatomic Pathology?

Client billing means the group bills the ordering hospital, clinic or practice a contracted fee. Patient billing means it bills the patient's insurance and then the patient.

For Medicare patients in a hospital, client billing is the route for the technical component, because an independent lab cannot bill Medicare for it after June 30, 2012 (42 CFR 415.130(d)(2)).

Chapter 16, section 40.2 says an independent lab billing a purchased technical component must perform at least one of the component services itself. UnitedHealthcare commercial policy adds that when both the purchaser and the performer bill the same service, only one is reimbursable unless modifier 59, XE, XP, XS, XU or 91 applies.

On cost sharing, Chapter 16, section 30.2 says the Part B deductible and 20 percent coinsurance do not apply to clinical laboratory tests paid on an assigned basis, while physician fee schedule codes are generally subject to them. A pathology interpretation on the fee schedule can therefore leave patient responsibility that a lab test would not. State law and payer contracts can add limits, so confirm both before you set up a client account.

How Do Medicare and Commercial Payer Rules Differ for Pathology Claims?

Medicare follows the fee schedule indicators, NCCI and the Claims Processing Manual. UnitedHealthcare commercial follows the same indicators and adds its own rules. See the Medicare billing guide and the UnitedHealthcare billing guide for more.

Does the No Surprises Act Apply to Pathology Claims?

Yes. Pathology is named as an ancillary service in 45 CFR 149.420(b)(1)(i), which lists items and services related to emergency medicine, anesthesiology, pathology, radiology and neonatology. For ancillary services, the rules say a nonparticipating provider at an in-network facility is always subject to the balance billing prohibition, and the notice and consent route is not available.

Our No Surprises Act hub explains the process, and the out-of-network billing and IDR service describes how we run it.

Which Pathology Denials Come up Most, and What Fixes Them?

The table above lists the CARC codes (claim adjustment reason codes on the remittance) that hit pathology claims, what each usually means and the fix. We work every denial within 48 hours.

See the denial management service.

How Do We Handle Pathology Billing?

Our AAPC and AHIMA certified coders code from the pathology report and check units, modifiers and the 26 and TC split before the claim goes out.

• Claims go out within 24 hours of charge entry, and denials are worked within 48 hours.
• We validate modifiers 26 and TC, units per specimen, G0416 for prostate needle biopsies and the CLIA number in item 23 before submission.
• Out-of-network underpayments go through open negotiation and federal IDR, with deadlines tracked.

We align each EHR, clearinghouse and payer portal workflow with verified team experience, standard claim validation, reconciliation controls and performance monitoring. See our medical coding service, or book a call.