Chromosome FISH, Amniotic Fluid with Reflex to Chromosome Analysis or Genomic Microarray

Fluorescence in situ hybridization (FISH) is performed for aneuploidy of chromosomes X, Y, 13, 18, and 21. FISH will be performed on amniotic fluid. If FISH results are normal, sample will be reflexed to genomic microarray. If FISH results are abnormal, sample will be reflexed to chromosome analysis. Additional charges apply.

Maternal Cell Contamination: For maternal cell contamination studies in the event that FISH is normal and testing is reflexed to genomic microarray, please submit maternal blood and order Maternal Cell Contamination, Maternal Specimen (ARUP test code 0050608) accompanied by a test request form for the mother (this test is performed at no charge). For questions regarding ordering please contact ARUP's genetic counselor at (800) 242-2787 ext. 2141.

The FISH analysis does not detect structural chromosome abnormalities, mosaicism, and other numerical chromosome abnormalities (excluding X, Y, 13, 18, and 21). In addition, false-positive or -negative results, as well as maternal cell contamination, have been demonstrated in prenatal FISH analysis. The American College of Medical Genetics recommends that irreversible therapeutic action should not be initiated on the basis of FISH results alone.

The chromosome analysis studies involve culturing of living cells; therefore, turnaround times given represent average times which are subject to multiple variables.

A processing fee will be charged if this procedure is canceled at the client's request after the test has been set up or if the sample integrity is inadequate to allow culture growth.

This test must be ordered using Cytogenetic test request form #43098 or through your ARUP interface. Specimen and completed test request form, including clinical indication, must be received within 48 hours of collection. Submit the Patient History for Prenatal Cytogenetics form with the electronic packing list (https://ltd.aruplab.com/Tests/Pdf/65).