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Test Code BILAO Biliary Tract Malignancy, FISH, Varies


Specimen Required


Supplies: PreservCyt Vial (T536)

Specimen Type: Bile duct brushing, bile duct aspirate, hepatobiliary brushing, or hepatobiliary aspirate (fine-needle aspiration is not acceptable)

Container/Tube: Separate ThinPrep vial, containing 20 mL PreservCyt or CytoLyt solution for each specimen

Specimen Volume: Entire collection

Collection Instructions:

1. If performing local cytology in addition to fluorescence in situ hybridization testing, aliquot half of the specimen into another ThinPrep vial before processing the specimen.

2. Submission of residual specimen (after processing other testing) may compromise the sensitivity of the test.

3. Label each specimen with specific source (eg, right hepatic duct or common bile duct).


Secondary ID

71917

Useful For

Assessing bile duct brushing or hepatobiliary brushing specimens for biliary tract malignancy

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
BILOB Biliary Tract Malignancy, FISH No No
BILOC Biliary Tract Malignancy, FISH No No
BILOD Biliary Tract Malignancy, FISH No No
BILOE Biliary Tract Malignancy, FISH No No
BILOF Biliary Tract Malignancy, FISH No No

Testing Algorithm

When this test is ordered, fluorescence in situ hybridization testing will be performed. When additional specimens are received, the laboratory will add BILOB to the second specimen, BILOC to the third specimen, and so on.

Special Instructions

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

Biliary Tract Malignancy, FISH

Specimen Type

Varies

Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred)
  Ambient 

Reject Due To

Pancreatic mass
Pancreatic cyst
Pancreatic fine-needle aspiration (FNA)  		 Reject

Clinical Information

Endoscopic retrograde cholangiopancreatography (ERCP) is used to examine patients with biliary tract obstruction or stricture for possible malignancy. Biopsies and cytologic specimens are obtained at the time of ERCP. Cytologic analysis complements biopsy by sometimes detecting malignancy in patients with a negative biopsy. Nonetheless, a number of studies suggest that the overall sensitivity of bile duct brushing and bile aspirate cytology is quite low.

 

Fluorescence in situ hybridization (FISH) is a technique that utilizes fluorescently-labeled DNA probes to examine cells for chromosomal alterations. FISH can be used to detect cells with chromosomal changes (eg, aneuploidy) that are indicative of malignancy. Studies in our laboratory indicate that the sensitivity of FISH to detect malignant cells in biliary brush specimens is superior to that of conventional cytology.

Reference Values

No abnormality detected by fluorescence in situ hybridization

Interpretation

An interpretive report will be provided.

Cautions

A positive fluorescence in situ hybridization (FISH) result does not identify location or type of malignancy. FISH abnormalities may be associated with high-grade dysplasia or carcinoma in situ. Cytology and biopsy may help clarify such situations.

Supportive Data

Cell counts using the biliary fluorescence in situ hybridization (FISH) probe set on pancreatobiliary brushings were compared between 49 patients with malignancy and 41 patients without malignancy to determine normal value cutoffs for this assay. The cutoff values were independently validated in a blinded study from brushing samples collected from 112 patients at the time of endoscopic retrograde cholangiopancreatography. Among patients with malignancy on follow-up, the sensitivity of a polysomy FISH result was significantly superior to cytology (74% vs. 28%, P<0.001). The specificity of FISH and cytology were similar (96% vs. 100%).

Clinical Reference

1. Barr Fritcher EG, Voss JS, Brankley SM, et al. An optimized set of fluorescence in situ hybridization probes for detection of pancreatobiliary tract cancer in cytology brush samples. Gastroenterology. 2015;149(7):1813-1824. doi:10.1053/j.gastro.2015.08.046

2. Barr Fritcher EG, Kipp BR, Voss JS, et al. ST27: The development of a tailored pancreatobiliary fluorescence in situ hybridization (FISH) assay to improve detection of malignancy in pancreatobiliary brushings. J Mol Diagn. 2013;15(6):909

3. Barr Fritcher EG, Kipp BR, Halling KC, et al. A multivariable model using advanced cytologic methods for the evaluation of indeterminate pancreatobiliary strictures. Gastroenterology. 2009;136(7):2180-2186. doi:10.1053/j.gastro.2009.02.040

Method Description

Biliary cells are harvested, fixed, and placed on a slide. Fluorescently labeled DNA probes to 1q21 (MCL1), 7p12 (EGFR), 8q24 (MYC), and 9p21 (CDKN2A) (Abbott Molecular, Inc) are hybridized to the cells on the slide. The slide is then washed and stained with DAPI (4',6-diamidine-2'-phenylindole dihydrochloride, a nuclear counterstain). Fluorescence microscopy with unique band filters is used to assess 100 consecutive epithelial cells for gains and losses of probe signals (chromosomal loci). Specimens are considered abnormal if cell counts exceed predetermined cutoff values for one or more of the following abnormalities: polysomy, homozygous 9p21 loss, single locus gain, single locus gain with 9p21 loss in the same cells, and/or tetrasomy. If the cutoff for polysomy is not attained in the 100-cell enumeration, then the remainder of the slide is assessed for polysomy until the cutoff is reached or the slide is exhausted.(Unpublished Mayo method)

Day(s) Performed

Monday through Friday

Report Available

7 to 10 days

Specimen Retention Time

Until reported

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

88377

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BILAO Biliary Tract Malignancy, FISH 95229-1

 

Result ID Test Result Name Result LOINC Value
71918 Result Summary 50397-9
71919 Result 95229-1
71920 Interpretation 69965-2
71921 Reason for Referral 42349-1
71922 Specimen 31208-2
MC029 Source 39111-0
MC030 Fixation 8100-0
MC031 Collection Method 33724-6
MC032 Clinical History 22636-5
71927 Method 85069-3
71928 Released By 18771-6