Test Overview
Test Methodology

Fluorescence In Situ Hybridization (FISH)

Test Usage

FISH testing is available for a wide range of microdeletion syndromes, such as DiGeorge, Prader-Willi, Angelman, Smith-Magenis, Miller-Dieker, and Williams Syndromes. FISH testing is also available for detection of microduplication 15q11-q13 and as adjunct testing for sex chromosome abnormalities. These FISH tests should be used for well defined syndromes. If multiple microdeletion FISH tests are desired a Chromosomal Microarray Analysis (available from the MMGL Molecular Genetics Laboratory) should be considered.

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Monday - Friday, 8:00am - 4:00pm. If necessary a STAT courier may be arranged for processing a sample on a priority basis. Call the laboratory at 763-5805 for additional information.
Soft Order Code
MiChart Code
Cytogenetics, FISH for Genetic Disorder (Non-malignant)
  • Microdeletion Syndromes, FISH Probe
  • FISH for Microdeletion Syndrome
  • FISH for Angelman Syndrome (15q11.2)
  • FISH for DiGeorge/VCF Syndrome (22q11.2)
  • FISH for Miller-Dieker Syndrome (17p13.3)
  • FISH for Prader-Willi Syndrome (15q11.2)
  • FISH for Smith-Magenis Syndrome (17p11.2)
  • FISH for Williams Syndrome (7q11.23)
  • FISH for Microduplication of 15q11-q13
  • FISH, Subtelomeric
  • Subtelomeric FISH
  • FISH for Sex Chromosome Abnormalities
  • XX/XY FISH in Turner Syndrome
  • FISH for Genetic Disorder (Non-malignant)
Specimen Requirements
Collection Instructions

FISH testing is performed as an adjunct to Chromosome Analysis when appropriate using the specimen submitted for Chromosome Analysis, unless otherwise approved by the Cytogenetics Laboratory Director. Specimen transport should be arranged so that the specimen is received by MLabs the same day it is collected. Call for a STAT courier if necessary. Collect specimen in a green top (sodium heparin) tube. Invert the tube several times to prevent clotting. Send the specimen intact at room temperature as soon as possible. DO NOT CENTRIFUGE. Clotted or hemolyzed specimens, or those from septic patients, are unacceptable.

Normal Volume
5 mL whole blood
Minimum Volume
2 mL whole blood
Rejection Criteria
Clotted or hemolyzed specimen, or specimen over 24 hours old,
Additional Information

For additional information on FISH testing and available probes, contact the MLabs Cytogenetics Laboratory. "Stand alone" FISH testing will include Tissue Culture at an additional charge. If no deletion is detected with metaphase cell FISH analysis for DiGeorge, an interphase cell FISH analysis will be performed to rule out a duplication in this region at an additional charge. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated.

CPT Code
88230, 88273, 88271, 88275
Fee Code
36540, 21572, EA040, EA041