title: Proficiency testing for laboratories performing fluorescence in situ hybridization with chromosome-specific DNA probes.
abstract: OBJECTIVE
  To assess laboratory performance, use, and limitations in the joint College of American Pathologists and American College of Medical Genetics proficiency testing program for laboratories performing cytogenetic tests based on fluorescence in situ hybridization (FISH).
  
  
  METHODS
  Eight proficiency surveys dealing with FISH detection of microdeletions or microduplications, aneuploidy in interphase cells, gene amplification, and neoplasm-specific translocations. Participating laboratories used their own DNA probes (commercial or home-brew), hybridization methods, and analytic criteria to answer clinical questions about cases represented by slides included in the survey materials. They also described their test results according to the International System for Human Cytogenetic Nomenclature (ISCN) and answered supplementary questions relating to their experience with the subject test systems.
  
  
  METHODS
  In addition to evaluating diagnostic accuracy, we evaluated survey use, laboratory experience, variation in methodologic approach, and the practicality of using ISCN nomenclature for describing test results.
  With the exception of one challenge, at least 80% of the participants reached the correct diagnostic conclusion. In the sole exception, there was still a consensus of 91.7% of participants with the same (albeit erroneous) diagnostic conclusion. The overall outstanding performance of participating laboratories clearly shows the reliability of current FISH methods. Despite the fact that a large number of laboratories reported little or no experience with the specific test systems, the overwhelming majority performed very well. This result shows that the program's strategy of targeting classes of abnormalities (vs a single abnormality associated with a specific disease) did not put at a disadvantage participants who did not routinely perform all of the potential tests in the class. The extraordinary variation in ISCN descriptions submitted by participants showed that the existing system for human cytogenetic nomenclature is not suitable for facile communication of FISH test results.
authors.affiliation: Genetic Services, Children's Hospital, San Diego, Calif 92123, USA. jmascarello@chsd.org
authors.forename: James T
authors.initials: JT
authors.lastname: Mascarello
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Brothman
authors.forename: Keri
authors.initials: K
authors.lastname: Davison
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Dewald
authors.forename: Marille
authors.initials: M
authors.lastname: Herrman
authors.forename: Danette
authors.initials: D
authors.lastname: McCandless
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Park
authors.forename: Diane L
authors.initials: DL
authors.lastname: Persons
authors.forename: Kathleen W
authors.initials: KW
authors.lastname: Rao
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Schneider
authors.forename: Gail H
authors.initials: GH
authors.lastname: Vance
authors.forename: Linda D
authors.initials: LD
authors.lastname: Cooley
mesh_terms: D002869:Chromosome Aberrations; D015342:DNA Probes; D018734:Genes, erbB-2; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000592:standards*; D007753:Laboratories / Q000592:standards*; D011786:Quality Control
chemical_list: D015342:DNA Probes