Pathology/Lab Coding Alert

Question: How should I code the following two scenarios, each of which involves examining the same number of special-stain slides?

1. Pathologist processes breast biopsy in two blocks and performs keratin stain on two slides from each block for a total of four stained slides.

2. Pathologist processes two separate skin lesion biopsies for suspected infection and performs PAS for fungus on one slide from each lesion and Gram stain for bacteria on one slide from each lesion for a total of four stained slides.


South Carolina Subscriber
Answer: The unit of service for the pathology exam is the specimen, not the block or slide. The unit of service for a special stain is also the specimen, not the block or slide, but you can use one special stain code for each individual special stain per specimen.

Although you have four special-stain slides in each case, the coding is very different:

Scenario 1: Report the breast biopsy as 88305 (Level IV -- Surgical pathology, gross and microscopic examination, breast, biopsy, not requiring microscopic evaluation of surgical margins). For the keratin stain, report one unit of 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody). Despite examining four special-stain slides, there is only one specimen and only one type of special stain -- meaning one unit of service.

Scenario 2: Report each separately identified skin lesion as 88305 (Level IV -- Surgical pathology, gross and microscopic examination, skin, other than cyst/tag/debridement/plastic repair) -- 88305 x 2. For the first lesion, also list two units of special stain code +88312 (Special stains [list separately in addition to code for primary service]; Group I for microorganisms [e.g., Gridley, acid fast, methenamine silver], each) because the pathologist uses two separate special stains for microorganisms. The stain coding is the same for the second lesion. That means you-ll report a total of four special stains -- 88312 x 4.