Locus-specific FISH (parent or family member of proband)
Test #:
330
Turnaround Time:
7-14 days
Specimen Requirements:
Specimens should be shipped at room temperature in a leak-proof, rigid container with overnight delivery. To discuss minimum acceptable specimens for neonatal patients or for sample types not listed, please contact Allele Diagnostics.
- Peripheral blood: 3-5 mL NaHep
CPT Codes:
88230 x1, 88271 x2, 88273 x2, 88291 x1
Ordering Requirements:
Clinical Utility:
- Testing parent of a proband with a known chromosomal abnormality visible by FISH to determine inheritance and/or recurrence risks for family.
- Testing a sibling or other family member of a proband with a known chromosomal abnormality visible by FISH.
Test Description:
Chromosome visualization by fluorescence in situ hybridization (FISH).
FISH can identify a variety of chromosomal abnormalities, both balanced and unbalanced, if a specific target region is identified. This testing is useful to perform for family members of a proband with an abnormal microarray result visualized by FISH. Familial FISH testing may allow for detection of balanced rearrangements in a normal family member, alternative unbalanced rearrangements, or a similar unbalanced rearrangement as seen in the proband. Family FISH studies for conditions caused by copy loss are typically performed by analyzing 20 metaphase cells and for conditions caused by copy gains are performed by analyzing 20 metaphase cells and counting signal patterns in 100 interphase cells.