Laboratory/Pathology

Pathology Interpretation Services

National Government Services has noted that there is some confusion and questions regarding the billing of professional components on some laboratory services. There is a certain subset of CPT codes for which are 100% technical but they can be billed with a 26 modifier if a physician interpretation is medically necessary. An interpretation may only be billed for these codes for hospital patients performed by hospital pathologists. They are not reimbursed for an office setting. This is further explained in CMS IOM Publication 100-04, Medicare Claims Processing Manual, Chapter 12, Section 60 (C) - Payment for Pathology Services:

C. Physician Laboratory and Pathology Services

Physician laboratory and pathology services are limited to:

  • Surgical pathology services;
  • Specific cytopathology, hematology and blood banking services that have been identified to require performance by a physician and are listed below;
  • Clinical consultation services that meet the requirements in subsection 3; and
  • Clinical laboratory interpretation services that meet the requirements and which are specifically listed in subsection 4.

4. Clinical Laboratory Interpretation Services

Only clinical laboratory interpretation services, which meet the criteria in subsections C.3.a, c, and d, are billable under the physician fee schedule. These codes have a PC/TC indicator of “6” on the Medicare Physician Fee Schedule database. These services are reported under the clinical laboratory code with modifier 26. These services can be paid under the physician fee schedule if they are furnished to a patient by a hospital pathologist or an independent laboratory.

The codes involved in this all have a PC/TC of 6 on the Medicare Physician Fee Schedule Database. The codes are:

CPT Code TC Modifier Code Descriptor
G0452 26 Molecular pathology interpr
83020 26 Hemoglobin electrophoresis
84165 26 Protein e-phoresis serum
84166 26 Protein e-phoresis/urine/csf
84181 26 Western blot test
84182 26 Protein western blot test
85390 26 Fibrinolysins screen i&r
85576 26 Blood platelet aggregation
86153 26 Cell enumeration phys interp
86255 26 Fluorescent antibody screen
86256 26 Fluorescent antibody titer
86320 26 Serum immunoelectrophoresis
86325 26 Other immunoelectrophoresis
86327 26 Immunoelectrophoresis assay
86334 26 Immunofix e-phoresis serum
86335 26 Immunfix e-phorsis/urine/csf
87164 26 Dark field examination
87207 26 Smear special stain
88371 26 Protein western blot tissue
88372 26 Protein analysis w/probe
89060 26 Exam synovial fluid crystals


Reviewed 10/11/2023