What Is the FISH Test for Pregnant Woman?

A FISH test helps detect possible birth defects.

A fluorescent in situ hybridization (FISH) test allows laboratory researchers to map genes and gene parts in a cell's genetic material. Doctors often order the test to check for genetic mutations and chromosome abnormalities.

Significance

When used in pregnancy, a FISH test looks at genetic material from the amniotic fluid to detect any existing "structural chromosome abnormalities," states the Children's Hospital Boston website. A laboratory performs the test and the results provide expectant parents with information on any suspected genetic abnormalities their baby might have. The FISH test provides rapid results.

Types

Three types of FISH probe tests exist, according to the National Human Genome Research Institute. The locus-specific probe identifies the chromosome that a specific gene is located on, the centromeric repeat probe determines how many chromosomes a person has or if a chromosome is missing any genetic material and the whole chromosome probe looks for chromosome abnormalities.

Considerations

An amniocentesis is necessary to retrieve the chromosomes for the FISH probe test, a procedure that carries a one in 200 chance of a miscarriage, according to Australia's Children Youth and Women's Health Service website. The FISH test is 98 percent accurate in predicting normality.

References

• Children's Hospital Boston: Karyotype, Extended Banding, Fluorescent In Situ Hybridization (FISH)
• National Humane Genome Research Institute: FISH Fact Sheet
• Australia's Children Youth and Womens Health Service: Amniocentesis