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FISH, Cri du Chat
Test CodeCPT Codes
88271, 88273
Includes
If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.
Preferred Specimen
Minimum Volume
Other Acceptable Specimens
Instructions
Specimen requirements: 3-5 mL whole blood collected in a sodium heparin tube.
Specimen viability decreases during transit. Send specimen to testing laboratory for viability determination. Do not freeze. Do not reject.
Transport Temperature
Specimen Stability
Refrigerated: See Instructions
Frozen: See instructions
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Methodology
Fluorescence in situ Hybridization (FISH)
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Reference Range
Clinical Significance
This test uses fluorescence in situ hybridization (FISH) technology to detect a deletion of the short arm of chromosome 5 in individuals with clinically suspected 5p- syndrome (cri du chat syndrome). Infants with this syndrome often have low birth weight, weak muscle tone, and a characteristic high-pitched cry that resembles that of a cat. Patients may also have developmental delay, intellectual disability, characteristic facial features, a small head, and dental malocclusions [1].
5p- syndrome, though rare, is one of the most common structural chromosomal anomalies. It is caused by a partial or complete deletion of the short arm of chromosome 5. Clinical manifestation, severity, and progression of the disease largely depend on the type, size, and region of the deletion(s). Diagnosis is based on clinical findings and can be confirmed by chromosomal karyotyping. When the karyotype appears normal but clinical suspicion for 5p-syndrome is high, FISH or chromosomal microarray analysis may aid in diagnosis [1]. However, a negative FISH result (ie, no deletion detected) does not rule out 5p- syndrome.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
Reference
1. Ajitkumar A, et al. Cri du chat syndrome. In: StatPearls [Internet]. StatPearls Publishing; 2021. Accessed October 18, 2021. https://www.ncbi.nlm.nih.gov/books/NBK482460/
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153