TC and 26 Split Billing in Dermatopathology

Choosing the right form of the claim

• In-house lab and in-house pathologist: bill globally, with no TC or 26 modifier appended.
• In-house lab, outside reading pathologist: your practice bills TC; the reading pathologist bills 26 separately.
• Specimen sent out entirely: your practice bills neither component for the pathology codes. The outside lab bills what it performed.
• In-house pathologist reading slides prepared elsewhere: bill 26 only.

Specimen units and code selection

A specimen is a separately identified and separately submitted tissue sample, not a slide and not a block. Four lesions submitted in four containers are four units of the applicable code; four sections cut from one specimen are one unit. Getting this wrong in either direction is the most common dermatopathology billing error, and it is visible to any auditor comparing the requisition against the claim.

88304 and 88305 cover the great majority of dermatology specimens, with 88305 applying to skin biopsies and most excisions read for a neoplastic or inflammatory diagnosis. Special stains and immunohistochemistry — the 88312 and 88342 families — are billed in addition where performed and documented, per stain and per block as the code descriptor allows.

Place of service and payer nuance

Place of service drives the payable components. A hospital-based encounter typically means the facility bills the technical component and the physician bills only the professional component; billing globally in that setting will deny or, worse, pay and be recouped later. Some Medicare Administrative Contractors also apply anti-markup limits where the professional component is purchased from an outside pathologist, capping what the billing practice may claim.