Biliary Tract Malignancy, Cytology & Molecular Testing
Method Description Describes how the test is performed and provides a method-specific reference
Standard brush cytology sampling is performed on patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for suspicious biliary tract strictures. Brushes are placed in a ThinPrep vial containing PreservCyt or CytoLyt solution. The specimen is sent in a single vial with or without the brush. If brush is present, it is removed and cells are collected from it by scraping them into a single vial containing 20 mL of PreservCyt solution. Two aliquots are prepared and used for each portion of the test. The cytology specimen is processed using the ThinPrep 2000 processor. Specimens are stained using a Papanicolaou stain and analyzed microscopically by a cytotechnologist and pathologist.
Biliary cells are harvested, fixed, and placed on a slide. Fluorescently-labeled DNA probes to the centromeres of chromosomes 3, 7, and 17 and to the 9p21 locus (UroVysion, Abbott Molecular, Inc., Des Plaines, IL) are hybridized to the cells on the slide. The slide is then washed and stained with DAPI (a nuclear counterstain). Fluorescence microscopy with unique band filters is used to scan the slide for atypical cells (eg, cells with nuclear enlargement or irregularity). These cells are assessed for gains of chromosomes 3, 7, and 17. Cells with chromosomal gains (polysomy or trisomy) are recorded. If 5 or more cells show polysomy, then the case is considered positive for polysomy. If 10 or more cells show trisomy of 1 of the chromosomes (most often chromosome 7), the case is considered positive for trisomy. (Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 8:00 a.m. – 5:00 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Up to 1 week depending on the results
Performing Laboratory Location The location of the laboratory that performs the test