FISH, Cri du Chat

Test Code

14614

CPT Codes
88271, 88273

Includes

If this test is ordered without routine G-band chromosome analysis, a tissue culture charge will be added at an additional charge (CPT code: 88230).
If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.

Preferred Specimen

5 mL whole blood collected in a sodium heparin (green-top) tube

Minimum Volume

1 mL

Other Acceptable Specimens

Whole blood collected in sodium heparin (royal blue-top), or sodium heparin lead-free (tan-top) tube

Instructions

Clinical history/reason for referral is required with test order.
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

Room temperature

Specimen Stability

Room temperature: See Instructions
Refrigerated: See Instructions
Frozen: See instructions

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Received frozen

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

Set up: Mon-Sat; Report available: 14 days

Reference Range

See Laboratory Report

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/

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.