Biliary Stricture (for UroVysion®) — FISH Analysis

CPT Code(s):  88368

Service Code (IU Health): 53023693(x4)

Ordering Recommendation: Detection of aneuploidy for chromosomes 3, 7 and 17, and loss of the 9p21 in patients with a suspected diagnosis of pancreatobiliary carcinoma.

Synonyms: FISH, biliary tract malignancy, bile duct, bile duct stricture malignancy, cholangiosarcoma, cholangiocarcinoma, pancreas.

Methodology: Fluorescence in situ hybridization (FISH)

Performed: Monday through Friday

Reported: 2 days

Collect: Biliary brushings or fluid collected via an ERCP (endoscopic retrograde cholangiopancreatography) in sterile centrifuge tube or sterile, tightly capped screw-top container.

Specimen Volume: 30 mL

Storage/Transport: Room temperature. Do not freeze.

Unacceptable Conditions: Frozen specimens.

Remarks: Pathology report of specimen to be studied should accompany specimen if available.

Stability: Ambient: 24 hours; Refrigerated: 48 hours; Frozen: Unacceptable

Reference Interval: Polysomy is defined as a gain of two or more chromosomes in four cells.  Trisomy is defined as a gain of one chromosome in ten cells. A deletion or loss of 9p21 must be observed in twelve cells.

Characteristics: FISH results are used in conjunction with other clinical features to determine the presence of malignancy. FISH results can be negative, trisomic or polysomic. A negative FISH result does not exclude pancreatobiliary carcinoma. These clinical features can include patient age and presence of primary sclerosing cholangitis (PSC) status.

Limitations: This analysis does not eliminate the possibility of low frequency mosaicism or small structural abnormalities.

References:

1. Moreno LE et al. Advanced cytologic techniques for the detection of malignant pancreatobiliary strictures. Gastroenterology. 2006;131:1064-1072.

2. Bangaurlingam SY et al. Long-term outcomes of positive FISH tests in primary sclerosing cholangitis. Hepatology. 2010;51:174-180.