Pathology/Lab Coding Alert

Question: Our lab processed a paraffin block and prepared H&E slides from a skin biopsy that the dermatologist submitted on May 18. The pathologist evaluated the slides the next day and ordered a PAS stain to rule out fungal infection, which our lab prepared that day (May 19). The pathologist examined the PAS slides on May 20. Because the H&E slide prep and the special stain slide prep had different service dates, Medicare denied our bill for the technical component of the special stain addon code due to the lack of a primary service on that date. How can we overcome this problem?

Ohio Subscriber

Answer: You can overturn this denial by getting the service dates right. The technical services occurred on May 18 -- hematoxylin and eosin (H&E) stain -- and May 19 -- periodic acid Schiff (PAS) stain. But according to Medicare's laboratory date of service rule, you should bill both services with a service date of May 18. That's when the dermatologist collected the specimen.

Here's how you should code the case:

• 88305-TC -- Level IV -- Surgical pathology, gross and microscopic examination, skin, other than cyst/tag/debridement/plastic repair; Technical component This code accounts for slide preparation using basic stain such as H&E.

• +88312-TC -- Special stains [List separately in addition to code for primary service]; Group I for microorganisms [e.g., Gridley, acid fast, methenamine silver], each; technical component.

Because +88312 is an add-on code, payers expect to see the procedure associated with a primary service such as a surgical pathology exam or a cytology exam. The pathologist would bill 88305-26 (... Professional component) and +88312-26 for the professional interpretation of the skin biopsy and special stain slides.

You aren't required to comply with the DOS rule for professional fees, but the simplest solution in most cases is to use the rule for all your billing. That way you'll always assign dates the same way whether you're billing globally (the CPT code without modifier) or with modifier TC or 26.