Pathology/Lab Coding Alert

Hint:Get the unit of service right.

A colon resection pathology report might represent multiple distinct services. You can’t afford to miss reimbursement for every separate procedure, so study the following case to make sure you get the coding right.

Pre-Op Diagnosis: Sigmoid colon mass
Procedure: Segmental colon resection

Pathology Report:

• Received sigmoid colon segment measuring 11 cm with attached mesenteric lymph nodes. Ulcerated tumor measuring 2.8 cm identified 2 cm from resection margin.
• Submitted intraoperative report to surgeon on frozen section proximal and distal margin exams A and B, margins clear.
• Processed tumor in three blocks labeled C, D, and E with hematoxylin and eosin (H&E), Periodic acid Schiff (PAS), CDX2, CK20, and CK7. Tissue is CDX2 negative, CK20 positive, and CK7 negative.
• Identified metastasis in three of 12 lymph nodes processed with H&E stain (3/12).
• Performed colon specimen microdissection for three molecular tests: microsatellite instability (MSI), KRAS, and BRAF gene analysis.

Final diagnosis: colorectal adenocarcinoma

• Stage T2 (muscularis propria invasion) N2a (spread to 4-6 lymph nodes) M0(no distant metastasis
• Grade G2 (moderately differentiated)

Tip 1: Identify Specimen(s)

The pathology report identifies the specimen as a “segmental colon resection.” If you look to CPT^®, you’ll see two possible code choices to describe the pathologist’s examination of this specimen. Both codes describe the examination of one specimen, no matter how many tissue blocks the pathologist examines:

• 88307 (Level V - Surgical pathology, gross and microscopic examination, … colon, segmental resection, other than for tumor …)
• 88309 (Level VI - Surgical pathology, gross and microscopic examination Level VI - Surgical pathology, gross and microscopic examination … colon, segmental resection for tumor …)

Key: The final diagnosis of adenocarcinoma in this case substantiates that the tissue exam is “for tumor” and warrants coding 88309. Making a mistake and reporting 88307 could cost you $145.

(Medicare Physician Fee Schedule (MPFS) 2023 national payment global service amount, conversion factor (CF) $33.06). (Note that at press time, CMS had not published the updated CF based on the Consolidated Appropriations Act, 2023, which increases the CF by 2.5 percent over the value published in the final rule.)

More: “The distinction between 88307 and 88309 is whether the pathologist examines the specimen for tumor, including documented work such as margin exam — no matter the final diagnosis,” says R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Arkansas.

Lymph nodes: The CPT^® definition for segmental colon resection doesn’t specifically state that you must bundle lymph nodes (as some listed specimens do). However, “colon resection routinely involves removing associated lymph nodes,” says Terri Brame Joy, MBA, CPC, COC, CGSC, CPC-I, product manager, MRO, in Philadelphia. That’s why coding convention suggests that you should not separately report lymph nodes attached to a colon resection specimen.

Tip 2: Scope Out Intraoperative Work

In this case, the pathologist documented a frozen section exam on two margins of the segmental colon resection. You should bill the service as follows:

• 88331 (Pathology consultation during surgery; first tissue block, with frozen section(s), single specimen)
• +88332 (… each additional tissue block with frozen section(s) (List separately in addition to code for primary procedure)

Because the pathologist examines multiple frozen section tissue blocks (identified as A and B) from the same specimen, you need to report both codes 88331 and 88332.

Notice: If the case involved a single frozen section block evaluation on two different specimens, you would instead code 88331 x 2.

Tip 3: Don’t Miss Special Stains

The pathology report documents lots of stains on three blocks of the segmental colon resection specimen. Let’s sort through how you should bill these services.

First, H&E is a standard stain for the pathology exam of the colon resection and lymph node specimens, so you shouldn’t bill a stain code in addition to the specimen exam code.

On the other hand, you should separately bill for the PAS stain and the immunohistochemistry tumor marker stains CK20, CDX2, and CK7.

PAS: Pathologists may use a PAS stain on colonic specimens to help identify mucin, which may distinguish types of colonic adenocarcinoma. You should code the PAS stain using 88313 (Special stain including interpretation and report; Group II, all other (eg, iron, trichrome), except stain for microorganisms, stains for enzyme constituents, or immunocytochemistry and immunohistochemistry). Specifically, you should report 88313 x 3 for the three blocks, because CPT^® includes this note: “Report one unit of 88313 for each special stain, on each surgical pathology block, cytologic specimen, or hematologic smear.”

Payday: Notice that if you missed that little detail about reporting 88313 per block, you might have reported just one unit of 88313 for the PAS stain, which pays $80.67 (MPFS 2023 national non-facility global service, CF $33.06). (Note that at press time, CMS had not published the updated CF based on the Consolidated Appropriations Act, 2023 that increases the CF by 2.5 percent over the value published in the final rule). That means you would have sacrificed $161.34 if you had missed billing for the PAS stain on the other two blocks.

Immunohistochemistry (IHC): Pathologists may perform a group of special IHC stains to help identify immunophenotype indicative of adenocarcinoma of colorectal origin. In this case, the pathologist examined three IHC stains: CK7, CK20, and CDX2 on each of the three segmental colon resection blocks. You should report the service using the following codes:

• 88342 (Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain procedure)
• Two units of +88341 (… each additional single antibody stain procedure (List separately in addition to code for primary procedure)

Alert: Notice that the unit of service is different for 88313 special stains vs. IHC special stains. You should bill the PAS special stain per block, but you must bill the IHC special stain procedures per specimen. If you report 88342 x 3 (once per block) and +88341 x 6 (two additional IHC stains per block) for this case, you’d be opening your practice to overpayment errors and fraud charges.

Tip 4: Code Your Part in Molecular Studies

If your pathologist documents performing microdissection to select and prepare tissue for send-out molecular testing, you can code the tissue prep using an appropriate code such as 88381 (Microdissection (ie, sample preparation of microscopically identified target); manual). Report microdissection per specimen.

If your lab performs the molecular tests rather than sending them out to a reference laboratory, you should use the appropriate codes that describe the specific tests performed, such as the following:

• 81210 BRAF (B-Raf proto-oncogene, serine/threonine kinase) (eg, colon cancer, melanoma), gene analysis, V600 variant(s))
• 81275 KRAS (Kirsten rat sarcoma viral oncogene homolog) (eg, carcinoma) gene analysis; variants in exon 2 (eg, codons 12 and 13))
• 81276 KRAS (Kirsten rat sarcoma viral oncogene homolog) (eg, carcinoma) gene analysis; additional variant(s) (eg, codon 61, codon 146))
• 81301 (Microsatellite instability analysis (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) of markers for mismatch repair deficiency (eg, BAT25, BAT26), includes comparison of neoplastic and normal tissue, if performed)

Pathologists may order KRAS and BRAF testing to help identify the likelihood that specific cancer medications such as Cetuximab and Panitumumab may be effective for this patient. Results of MSI testing may indicate a possible genetic component to the patient’s colon cancer, which may also impact treatment choices.

See the Code Roundup

The final coding for this case is as follows:

88309
88331
+88332
88313 x 3
88342
+88341 x 2
88381

If your lab performs the molecular testing, you should also list the appropriate codes for those services.