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HelpTest Code DD22F 22q11.2 Deletion/Duplication, FISH, Varies
Useful For
Establishing a diagnosis of 22q deletion/duplication syndromes
Detecting cryptic rearrangements involving 22q11.2 or 22q11.3 that are not demonstrated by conventional chromosome studies
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| _PBCT | Probe, +2 | No, (Bill Only) | No |
| _PADD | Probe, +1 | No, (Bill Only) | No |
| _PB02 | Probe, +2 | No, (Bill Only) | No |
| _PB03 | Probe, +3 | No, (Bill Only) | No |
| _ML10 | Metaphases, 1-9 | No, (Bill Only) | No |
| _M30 | Metaphases, >=10 | No, (Bill Only) | No |
| _IL25 | Interphases, <25 | No, (Bill Only) | No |
| _I099 | Interphases, 25-99 | No, (Bill Only) | No |
| _I300 | Interphases, >=100 | No, (Bill Only) | No |
Testing Algorithm
This test includes a charge for the probe application, analysis, and professional interpretation of results for one probe set (2 individual fluorescence in situ hybridization probes). Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.
Appropriate ancillary probes may be performed at consultant discretion to render comprehensive assessment. Any additional probes will have the results included within the final report and will be performed at an additional charge.
Special Instructions
Method Name
Fluorescence In Situ Hybridization (FISH)
Reporting Name
22q11.2 Deletion/Duplication, FISHSpecimen Type
VariesOrdering Guidance
This test does not detect other chromosomal or structural anomalies and is intended to be ordered in conjunction with chromosomal microarray or chromosome analysis.
For detection of unbalanced translocations, deletions, or duplications, chromosomal microarray may be the more appropriate test; order CMACB / Chromosomal Microarray, Congenital, Blood; or CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling.
Additional Testing Requirements
Normal fluorescence in situ hybridization (FISH) results will not exclude the majority of cytogenetically detectable abnormalities. As FISH testing is not a substitute for complete cytogenetic analysis, additional cytogenetic testing should be performed in conjunction with this test; order CMACB / Chromosomal Microarray, Congenital, Blood; or CHRCB / Chromosome Analysis, Congenital Disorders, Blood
Shipping Instructions
Advise Express Mail or equivalent if not on courier service.
Necessary Information
A reason for testing must be provided. The laboratory will not reject testing if this information is not provided however an applicable indication for testing may be entered by Mayo Clinic Laboratories. Appropriate testing and interpretation may be compromised or delayed.
Specimen Required
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Whole blood
Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA) or yellow top (ACD)
Specimen Volume: 4 mL
Collection Instructions
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
3. Other anticoagulants are not recommended and are harmful to the viability of the cells.
4. Cord blood is acceptable
Additional Information:
1. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
2. Specimen cannot be frozen.
Acceptable:
Specimen Type: Fixed cell pellet
Container/Tube: Sterile container with a 3:1 fixative (methanol:glacial acetic acid)
Specimen Volume: Entire specimen
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20 to 25 mL
Collection Instructions:
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis.
2. Discard the first 2 mL of amniotic fluid.
3. If ordering with CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling, submit a minimum of 12 mL.
4. If ordering with CHRAF / Chromosome Analysis, Amniotic Fluid, submit a minimum of 12 mL.
5. If ordering with both CMAP and CHRAF, submit a minimum of 26 mL.
Additional Information:
1. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
2. Bloody specimens are undesirable.
3. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
4. Specimen cannot be frozen.
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20 to 25 mg
Collection Instructions:
1. Collect specimen by the transabdominal or transcervical method.
2. Transfer chorionic villi to a Petri dish containing transport medium (such as CVS Media (RPMI) and Small Dish (T095).
3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.
4. If ordering with CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling, submit a minimum of 12 mg.
5. If ordering with CHRCV / Chromosome Analysis, Chorionic Villus Sampling, submit a minimum of 12 mg.
6. If ordering with both CMAP and CHRCV, then submit a minimum of 26 mg.
Additional Information:
1. Label each container with the specimen type, patient's name, and laboratory control number.
2. Specimen cannot be frozen.
Specimen Type: Products of conception or stillbirth
Supplies: Hank's Solution (T132)
Container/Tube: Sterile container with sterile Hank's balanced salt solution, Ringer's solution, sterile RPMI transport media, or normal saline
Specimen Volume: 1 cm(3) of placenta (including 20 mg of chorionic villi) and a 1 cm(3) biopsy specimen of muscle/fascia from the thigh
Collection Instructions:
1. Do not handle specimen with hands.
2. If a fetus cannot be specifically identified, collect 50-mg villus material or tissue that appears to be of fetal origin.
Additional Information:
1. Do not send the entire fetus.
2. If a fetus is sent, please provide a parental release form or complete the Final Disposition of Fetal/Stillborn Remains form and send it with the fetus. (A copy of this form can be found in Special Instructions.) Please note that completion of the form requires a parent's signature.
3. Specimen cannot be frozen.
4. While fresher specimens prepared as described above are preferred, we can attempt analysis on specimens that have been in less-than-ideal conditions.
5. Label each container with the specimen type, patient's name, and laboratory control number.
Specimen Type: Autopsy
Supplies: Hank's Solution (T132)
Container/Tube: Sterile container with sterile Hank's balanced salt solution, Ringer's solution, sterile RPMI transport media, or normal saline.
Specimen Volume: 1 cm(3) biopsy specimen of muscle/fascia from the thigh
Collection Instructions:
1. Wash biopsy site with an antiseptic soap.
2. Thoroughly rinse area with sterile water.
3. Do not use alcohol or iodine preparations.
4. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.
Additional Information:
1. Label each container with the specimen type, patient's name, and laboratory control number.
2. Specimen cannot be frozen.
Specimen Type: Skin biopsy
Supplies: Hank's Solution (T132)
Container/Tube: Sterile container with sterile Hank's balanced salt solution, Ringer's solution, sterile RPMI transport media, or normal saline.
Specimen Volume: 1 cm(3) biopsy specimen of muscle/fascia from the thigh
Collection Instructions:
1. Wash biopsy site with an antiseptic soap.
2. Thoroughly rinse area with sterile water.
3. Do not use alcohol or iodine preparations.
4. A local anesthetic may be used.
5. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.
Additional Information:
1. Label each container with the specimen type, patient's name, and laboratory control number.
2. Specimen cannot be frozen.
Specimen Minimum Volume
Amniotic fluid: 5 mL; Autopsy, skin biopsy: 4 mm; Whole blood: 2 mL; Chorionic villi: 5 mg; Fixed cell pellet: 1 pellet; Products of conception: 1 cm(3)
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | ||
| Ambient | |||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
An interpretive report will be provided.
Method Description
This test is performed using a commercially available enumeration strategy probe set including the critical region locus (HIRA) on the long arm of chromosome 22 (22q11.2) and the control probe arylsulfatase-A at 22q13.3. Ten metaphase cells are examined for deletion or duplication of the HIRA fluorescence in situ hybridization probe. Since 22q duplications of HIRA may be difficult to detect on metaphase cells, 200 interphase nuclei are scored to identify duplications.(Crifasi PA, Michels VV, Driscoll DJ, Jalal SM, Dewald GW. DNA fluorescent probes for diagnosis of velocardiofacial and related syndromes. Mayo Clin Proc. 1995;70(12):1148-1153)
Day(s) Performed
Monday through Friday
Report Available
7 to 10 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88271 x 2, 88291-DNA probe, each (first probe set), Interpretation and report
88271 x 2-DNA probe, each; each additional probe set (if appropriate)
88271 x 1-DNA probe, each; coverage for sets containing 3 probes (if appropriate)
88271 x 2-DNA probe, each; coverage for sets containing 4 probes (if appropriate)
88271 x 3-DNA probe, each; coverage for sets containing 5 probes (if appropriate)
88273 w/modifier 52-Chromosomal in situ hybridization, less than 10 cells (if appropriate)
88273-Chromosomal in situ hybridization, 10-30 cells (if appropriate)
88274 w/modifier 52-Interphase in situ hybridization, <25 cells, each probe set (if appropriate)
88274-Interphase in situ hybridization, 25 to 99 cells, each probe set (if appropriate)
88275-Interphase in situ hybridization, 100 to 300 cells, each probe set (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| DD22F | 22q11.2 Deletion/Duplication, FISH | 82246-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 51851 | Result Summary | 50397-9 |
| 51853 | Interpretation | 69965-2 |
| 54538 | Result | 62356-1 |
| CG669 | Reason For Referral | 42349-1 |
| CG670 | Specimen | 31208-2 |
| 51854 | Source | 31208-2 |
| 51855 | Method | 85069-3 |
| 51852 | Additional Information | 48767-8 |
| 53875 | Disclaimer | 62364-5 |
| 51856 | Released By | 18771-6 |
Secondary ID
35246Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Final Disposition of Fetal/Stillborn Remains (if fetal specimen is sent) Only for products of conception or stillbirth specimen.
3. If not ordering electronically, complete, print, and send a Cardiovascular Test Request Form (T724) with the specimen.