Molecular Cytogenetics (FISH)

FISH
Test performed by: LabPLUS - Dept. Diagnostic Genetics - Cytogenetics

Results or General Enquiries : use ward computer or contact Lablink : ext 22000, DDI (09) 307-8995 or 0800 522 7587.

Other contacts: Section Leader: Sajayan Joseph ext 22007, Technical Specialist: Lisa Duffy ext 22007.

Turnaround time is dependent on the type of test being requested. As a general guideline:

Prenatal aneuscreen samples are available within two working days.

HER2 samples are available within five working days (urgent Her2 cases may be prioritised if required).

Other cases can generally be completed within seven working days, although HGSA guidelines allow 18 days for completion.

Use the link below to view all currently available FISH probes.

FISH probe list

Specimen Collection
Please ensure that a telephone or locator number is written on the request form so that the requesting doctor can be contacted.
Clinical details are required in order to establish the appropriate testing strategy for the patient, and to enable the report/s to be cross referenced to other tests that have been performed.

Specimen Requirements for Formalin Fixed Paraffin Embedded (FFPE) Tissues:

Requests for FISH testing can be made using the Diagnostic Genetics request form found on the Lab Plus website and Test Guide.

6 x slides of ~4 um thickness p araffin embedded tissue.

1 x H&E stained slide with the area of interest marked.

All specimens should be processed through a Histopathology laboratory.

All specimens sent must be accompanied by the following:

Two forms of matching identification on both the slides and the form .
If these do not match, LabPlus policy requires a specimen labelling error form to be sent to the clinician,
and although the specimen may be processed, a result will not be released until the form is received back.

A marked H+E slide with the area/s to be targeted
If multiple areas are targeted, please indicate whether they need to be analyzed separately.

A copy of the histology report

Additional relevant information .
This includes whether the specimen has been decalcified or has undergone additional histological processing,
areas of different morphology within the tumour sample, and the presence of more than one tumour within the sample.

Failure to include relevant information may result in a reporting delay, as consultation with LabPlus pathologists may be required.

See also HER-2 FISH breast cancer
See also POC Chromosome analysis

Specimen Requirements for Analysis on NON-formalin fixed paraffin embedded tissue:

Requests for FISH testing can be made using the Diagnostic Genetics request form found on the Lab Plus website and Test Guide.

Please refer to the relevant links below for the following specimen types:

Amniotic Fluid or Chorionic Villus specimen

Peripheral and Cord blood specimens

Bone Marrow Aspirate, Bone Marrow Trephine, Unstimulated peripheral blood specimen OR Solid Tumour Biopsy

See Chromosome Analysis - Amniotic Fluid and Chorionic Villus specimens
See Chromosome Analysis - Blood
See Chromosome Analysis - Bone Marrow
See Chromosome Analysis - Solid Tumours

GENERAL INFORMATION

Fluorescence in situ hybridization (FISH) is a powerful tool for the rapid detection of specific chromosome abnormalities which are otherwise undetectable or difficult to characterize by conventional cytogenetic methods. It represents a type of genetic testing called molecular cytogenetics, combining the ability to identify a specific gene or gene locus(molecular) with direct visualization of the cells and/or chromosomes under a fluorescence microscope (cytogenetics).

APPLICATIONS OF FISH

FISH testing has a wide range of applications due to the use of probes on a variety of different tissue types. FISH, unlike conventional cytogenetics, can be applied to uncultured cells in interphase to identify chromosome abnormalities. Therefore, it can be used on products of conception tissues, fixed tissues, differentiated cells, paraffin embedded sections, or other specimens which may not be successfully grown in culture.
General uses of FISH include:

1. Postnatal testing:

FISH is more sensitive than conventional cytogenetics in the detection of microdeletion syndromes. These are conditions which are due to gene or gene region deletions which are often not identifiable even by high-resolution banding of chromosomes. Examples of microdeletion syndromes include Prader-Willi, Angelman, DiGeorge, velo-cardio-facial, Miller-Dieker, Smith-Magenis, and Williams syndromes. FISH also readily detects deletions in Wolf-Hirschhorn and cri-du-chat syndromes.
Chromosomes can be "painted" using FISH probe cocktails. This technique is of particular significance when a complex chromosome rearrangement is present.
Telomere probes can be used to detect subtle translocations or deletions involving the ends of chromosomes.
Marker chromosomes and other chromosome aberrations that are difficult to interpret by conventional cytogenetic techniques can in many cases be identified by the use of FISH.

Refer also: Chromosome Analysis-Blood

2. Prenatal testing:

Interphase FISH can be used for prenatal diagnosis of suspected aneuploidy.

Refer Also: Chromosome Analysis-Prenatal

3. Haematology and Oncology testing:

FISH is used in cancer cytogenetics for the diagnosis and monitoring of haematological disorders and in the diagnosis of solid tumours. Its uses include:

The detection of specific gene rearrangements that occur in different disorders.
The detection of copy number changes and gene amplifications.
The assessment of patients following sex-mismatched bone marrow transplantation.
Residual disease monitoring.

4. FISH probes applied to formalin fixed paraffin embedded tissue.

Paraffin embedded tissue FISH (PET-FISH) is generally used for solid tumour and products of conception specimens, where tissues fails to grow or there is insufficient or unsatisfactory tissue available for G-banding or routine FISH analysis.

PET-FISH allows:

Site-specific testing of tissues.

Testing for specific rearrangements where there is a differential diagnosis.

Confirmation of abnormalities that may be present in low proportions in bone marrow or solid tumour cultures due to loss of the malignant cells in culture.

Aid in the diagnosis of disease for tissue with poor histological morphology.

See other tests and specimen requirements under Cytogenetics.

Cytogenetics Information Page

Last updated at 09:23:44 07/06/2022