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Test Code CH-FISH Chromosomes - FISH

Important Note

NOTE: please see Cytogenetics Familial Studies/CH-FAMS for information about parental follow up FISH studies

Clinical System Name

Cytogenetics Constitutional FISH Blood Draw

NOTE: See CH-NEOP for neoplasia FISH


Cytogenetics FISH
Deletion 15q11
Deletion 22q11.2 syndrome
Deletion 22q13 syndrome
DiGeorge Syndrome
Duplication 15q11
Duplication 22q11.2 syndrome
Velocardiofacial (VCFS)
Williams Syndrome


This is a targeted test to detect constitutional deletions or duplications of chromosomal material in the region of interest. 

Sample Requirements

Specimen: Whole Blood

Container(s): Dark Green/Sodium Heparin (no serum separator)

Preferred Vol:  5.0 mL (3.0 mL for infants <24 months)

Minimum Vol:  3.0 mL (1.0 mL for infants <24 months); no micro collection

Note:  Keep sample at room temperature; deliver to the lab promptly.  Samples received after 3 pm will be set up the following day.

Note:  For patients who have had a whole blood transfusion, wait 10 days post transfusion to draw for Cytogenetics.  No wait time is necessary if the patient received red cells or plasma. 


Processing Instructions

Reject due to: Collected in microtainer.

Spin: N

Aliquot: N

Temp: RT

Storage location:  Days: Transport specimen, requistion, and labels to 10th floor Cytogenetics (station #180). 

Eves/Nights: Store specimen, copy of requisition, and labels in the Cytogenetics box in CPA.


Off-site collection: Keep whole blood at room temperature. Transport to Children's Lab ASAP. Samples received after 3 pm will be set up the following day.


Temperature Time
Room temp 3 d (call laboratory if sample is older)
Refrigerated No
Frozen No



STAT Performed TAT
N Daily 1 - 2 w


Performing Laboratory

Seattle Children's Hospital


Department: Cytogenetics Laboratory 

Phone number: 206-987-3961


Lab Client Services: 206-987-2617,


Lab Genetic Counselor:



Method: Fluorescent in-situ hybridization

CPT Codes

Interphase FISH: 88271, 88275, 88291, 88230

Metaphase FISH: 88271, 88273, 88291, 88230


Call or email Lab Client Services for CPT codes for other FISH panels

Clinical Utility

FISH can be used to confirm or rule out targeted chromosomal abnormalites