Pathology/Lab Coding Alert

Question: For a breast case, we used an AE1/AE3 immunostain on serial sections from multiple blocks prepared from the sentinel lymph node. For the breast biopsy, we quantified ER/PR, Her-2/neu and Ki-67 using computer assisted technology. How should we code this?

Colorado Subscriber

Answer: The breast case you describe involves two distinct specimens -- the sentinel lymph node and the breast biopsy.

For the sentinel lymph node, you should report 88307 (Level V -- Surgical pathology, gross and microscopic examination, sentinel lymph node) for the pathologist's examination. Additionally, you can report 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody) for the AE1/AE3 immunohistochemistry (IHC) stain.

Just one unit: Despite the fact that pathologist examined the IHC on serial sections from multiple blocks, you can only bill one unit of 88342 for the sentinel node. That's because the unit of service for IHC stains is not the block or slide but "each antibody."

Tricky: Although AE1/AE3 involves two histochemical antibodies, it functions as a single-color stain to detect the presence of cells expressing both low- and high-molecular-weight cytokeratins. That means you should report AE1/AE3 as a single unit of 88342.

Breast specimen: For the breast biopsy, you should report 88305 (Level IV -- Surgical pathology, gross and microscopic examination, breast, biopsy, not requiring microscopic evaluation of surgical margins).

You state that you performed automated quantitative IHC evaluations on the breast tissue. The correct code for these tests is 88361 (Morphometric analysis, tumor immunohistochemistry [e.g., Her-2/neu, estrogen receptor/progesterone receptor], quantitative or seminquantitative, each antibody; using computer-assisted technology).

Each antibody: Again, the unit of service for the 88361 IHC test is "each antibody." In this case, you examined four antibodies: estrogen receptor (ER), progesterone receptor (PR), Her-2/neu, and Ki-67. That means you should bill 88361x4.

Bundling alert: Because the Correct Coding Initiative (CCI) bundles 88342 with 88361, you-ll have to override the edit pair for tests performed on the same day. You should append modifier 59 (Distinct procedural service) to 88342 to indicate that the test represents a distinct service -- in this case, a separate antibody and a separate specimen.