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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: FISH- Prader-Willi Syndrome, Deletion 15q11.2

Test Code(s): 871F30 / HC871F30

CPT Code(s): 88271, 88273

Test Description: Test Component:

DNA probes specific for 15q11.2 (SNRPN) are used.

Clinical Significance: Detection of deletion 15q11.2 associated with Prader-Willi syndrome.

Testing Site: Testing will be sent to an approved reference laboratory.

Days Performed: Mon-Sat.

Turnaround Time: Routine: 10 - 14 days.

Specimen Requirements

Specimen: Blood

Collection Instructions: Blood must be received and processed by WSLH within 24 hours of collection. Specimen must be received in UWHC Core Laboratory (B4/220) on Monday-Friday only.

Collection Container: Preferred: Green top (with sodium heparin anticoagulant)

Collection Volume: Preferred: 4 mL
Pediatrics: 1 mL

Sample Analyzed: Whole Blood

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220) at room temperature. Transport with coolant pack during hot weather (>85F).  

Unacceptable Criteria: Blood that has been frozen or clotted.
Blood that is collected in EDTA, sodium citrate or other anti-coagulants.

Stability: Ambient: 24 hours
Refrigerated: Not acceptable
Frozen: Not acceptable


Interpretation provided with results.

Test Limitations:

Negative FISH results do not rule out a diagnosis of Prader-Willi syndrome.

Additional Information:

The primary test for Prader-Willi syndrome is the Methylation specific PCR test.  The FISH test is used to follow-up abnormal results to differentiate between deletion and uniparental abnormalities.  It is recommended that the FISH analysis be performed in conjunction with chromosome analysis.  If the chromosome analysis is not done at the same time as the FISH analysis there will be an additional processing charge.




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