Pathology/Lab Coding Alert

Experts explain tissue versus nontissue guidelines

If you've been waiting for direction on how to code fluorescence in situ hybridization (FISH) procedures, the answers are here. At last, key authoritative sources offer clear advice on when and how to use molecular cytogenetics codes (88271-88275) or surgical pathology code 88365 for in situ hybridization testing. Even as FISH testing has become a clear diagnostic choice for certain breast and bladder cancers, coding for the procedure has become murkier. "No matter what source you consult - probe vendor, national reference lab, or well-respected trade publication - you find different FISH coding advice," says Dennis Padget, MBA, CPA, FHFMA, president of Padget & Associates, a pathology financial and compliance consulting firm in Simpsonville, Ky. But according to Padget, recent direction from authoritative sources - AMA, College of American Pathologists (CAP) and CMS - points to a coding consensus.

Use Molecular Cytogenetics Codes for Nontissue Samples

Use CPT codes 88271-88275 (Molecular cytogenetics; ...) and 88291 (Cytoge-netics and molecular cytogenetics, interpretation and report) to report each step of in situ hybridization based on which methods the lab uses. (For complete CPT code descriptions, see "Know Your FISH and Related Diagnostic Test CPT Codes and Uses" on page 75.) Even though these codes do not specify the sample source, coding authorities limit their use to cell samples from fluids and smears (disassociated or exfoliated cells) - not tissue samples from histologic processing.

CMS states in program memorandum AB-99-84 that "88272-88275 ... are for molecular cytogenetic tests other than those performed on histologic sections."

"Although it appears the AMA initially intended codes 88271-88275 to accurately report FISH from any source, stating that forerunner codes 83896 [Molecular diagnostics; nucleic acid probe, each] and 88365 did not provide an accurate description of FISH, more recent AMA direction restricts their use to nonhistologic samples," Padget says.

The June 2002 CPT Assistant agrees that you should use these codes for cells, not tissue, stating, "The cytogenetics studies series of codes [88271-88275] describes the study of cells performed in a clinical laboratory." You should report 88291 for the physician interpretation of an entire patient study, according to the AMA.

CAP has also weighed in on the issue, stating in the April 2002 issue of CAP Today, "The molecular cytogenetics codes should be reported when in situ hybridization is performed as a clinical laboratory study." Clinical laboratory studies involve samples such as urine and peripheral blood, not tissue specimens examined by a physician and reported using surgical pathology codes.

Use Surgical pathology Codes for Tissue FISH Studies

The three sources - AMA, CMS and CAP - also agree that you should report tissue FISH studies using 88365 (Tissue in situ hybridization, interpretation and report).

CMS states in memo AB-99-84, "When a test for HER-2/neu overexpression on a histologic section is performed using the FISH technique and a DNA probe, the test should be billed as 88365."

Likewise, the AMA advises that "When a pathologist performs an interpretation of tissue in situ hybridization as an adjunctive study to a gross and microscopic examination of tissue to test for HER-2/neu cancers, then code 88365. Codes from the cytogenetics studies series should not be used in this instance," according to the June 2002 CPT Assistant. In agreement with these two sources, CAP Today April 2002 reports, "Use code 88365 ... when a pathologist interprets tissue in situ hybridization as an adjunctive study."

Unit of Service Varies for FISH Codes

Molecular cytogenetics codes 88271-88275 for cellular FISH are "building block" codes, Padget says. You should select the appropriate hybridization code (88272-88275, Molecular cytogenetics; chromosomal [or] interphase in situ hybridization ...) based on the number of cells analyzed and whether the lab used metaphase or interphase hybridization. "In addition to the hybridization, a single FISH study might involve multiple DNA probes, and you should report one unit of 88271 (Molecular cytogenetics; DNA probe, each [e.g., FISH]) for each probe," Padget says. If the pathologist interprets the results of all of these steps in a single FISH patient study, you should report one unit of 88291.

"Reporting tissue FISH is totally different," Padget says. "Code 88365 encompasses each step of the analysis, including multiple probes and physician interpretation." The only code you might be likely to report with 88365 is 88358 (Morphometric analysis; tumor) if the pathologist also interprets tumor morphometry.

Know Technical/Professional Reporting Rules

Nontissue FISH test codes 88271-88275 are technical-only codes paid under the Clinical Laboratory Fee Schedule. "If a pathologist interprets these tests, you should report the service using 88291 - a professional-only code paid under the Medicare Physician Fee Schedule," says Laurie Castillo, MA, CPC, CPC-H, CCS-P, president of Professional Coding and Compliance Consulting in Manassas, Va.

To the contrary, codes 88365 and 88358 have a technical and professional component paid under the Medicare Physician Fee Schedule. If you're only billing on the CMS-1500 claim form for the lab service technical component, append modifier -TC (Technical component) to the code. If you're only billing for the pathologist's test interpretation, append modifier -26 (Professional component) to the code. "Without a modifier, these codes represent the global service, including both the technical and professional component," Castillo says.

Don't Mix and Match Codes

"For a FISH test on any given sample, you should not report 88365 or 88358 together with a code from the 88271 family or with 88291 and vice versa," Padget says.

CAP states that "Code 88365 should not be used with codes from the cytogenetics section." Not only do the two code groups describe FISH for different sample types, but they also report the technical and professional components differently, making them mutually exclusive for a single FISH study.

"You should not report codes from the molecular diagnostics family (83890-83912) instead of or in addition to 88365, or codes from molecular cytogenetics (88271-88275 and 88291)," Padget says.

ISH Reporting Is the Same

Report in situ hybridization (ISH) tests that are non-fluorescing the same as you would FISH tests for either tissue or nontissue samples. For example, you should report a cervical smear ISH test to detect human papillo-mavirus (HPV) with codes 88271 and 88275 for analysis of more than 100 cells. You should also report 88291 if the pathologist interprets the test. "Note that the 88271 code description cites FISH as an example of the code's use, indicating that it is not limited to fluorescent tests," Padget says.

For tissue ISH tests, report code 88365. Like 88271, the code definition does not limit the test to fluorescent DNA probes.

Payers May Not Agree

Although CMS, AMA and CAP documentation supports reporting nontissue FISH using the 88271 code family and tissue FISH using 88365, not all payers agree. For example, National Heritage Insurance Company instructs labs to report 88299 (Unlisted cytogenetic study) for a urine FISH bladder cancer test.

That's why you should always check your payers' rules before reporting FISH testing. "When payers direct you to report FISH differently than CMS and AMA instructs, you should get their instructions in writing," Padget says. "You'll also want to share the AMA and CMS consensus information with the payer's medical director and encourage a conforming change." If you face divergent rules from your carrier or other payers, you can use these facts to contend for streamlined FISH reporting.