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Test ID NADF Newborn Aneuploidy Detection, FISH

Useful For

Screening for chromosomal aneuploidies of chromosomes 13, 18, 21, X, and Y in newborn peripheral blood specimens

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
_I099 Interphases, 25-99 No, (Bill Only) No
_I300 Interphases, >=100 No, (Bill Only) No
_IL25 Interphases, <25 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
_PBCT Probe, +2 No, (Bill Only) No

Testing Algorithm

This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results.


Additional charges will be incurred for all reflex probes performed. 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.

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

Newborn Aneuploidy Detection, FISH

Specimen Type

Whole blood

Specimen Required

Provide a reason for referral with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.


Container/Tube: Green top (sodium heparin)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Other anticoagulants are not recommended and are harmful to the viability of the cells.

3. Advise Express Mail or equivalent if not on courier service.

4. Cord blood is acceptable.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred)

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Approximately half of clinically recognizable spontaneous abortions have a major chromosomal anomaly.


Up to 95% of chromosomal abnormalities diagnosed prenatally involve aneuploidy (gain or loss of whole chromosome) of chromosomes 13, 18, 21, X, and Y.


In liveborn infants, about 8/1,000 have a major chromosome anomaly, of which 6.5/1,000 involve aneuploidy of 1 of these 5 chromosomes.


Diagnosis of chromosomal disorders can be performed by chromosome analysis of uncultured blood, standard chromosome study, and the technique utilizing FISH based on interphase cells. Standard chromosome analysis takes 3 to 10 days and analysis from uncultured newborn blood is often unsatisfactory and labor-intensive. FISH based methods facilitate rapid diagnosis of aneuploidy and may be helpful in medically urgent evaluations of newborn infants suspected to have aneuploidy of any of these chromosomes.


This test does not detect chromosomal aneuploidies other than 13, 18, 21, X, and Y or any structural anomaly that does not result in gain of these chromosomes.


Low levels of mosaicism involving chromosomes 13, 18, 21, X, or Y may not be detected by this assay.

Reference Values

An interpretive report will be provided.


An interpretive report will be provided.


The use of these probes has been approved by the FDA as a stand-alone test. However, we recommend that a complete chromosome analysis (CHRCB / Chromosome Analysis, Congenital Disorders, Blood) or chromosomal microarray (CMACB / Chromosomal Microarray, Congenital, Blood) be performed in conjunction with this FISH test. In cases where the FISH analysis is normal, a chromosome analysis or chromosomal microarray allows for the potential identification of more complex abnormalities and the less common numeric abnormalities of other chromosomes. In cases where the FISH study is abnormal, chromosome analysis can determine whether the abnormality is due to aneuploidy or a complex structural abnormality, allowing for recurrence risk information for the family.


Interfering factors

- Cell lysis caused by forcing the blood quickly through the needle

- Use of an improper anticoagulant or improperly mixing the blood with the anticoagulant

- Excessive transport time

- Inadequate amount of specimen may not permit adequate analysis

- Improper packaging may result in broken, leaky, and contaminated specimen during transport

Clinical Reference

1. Jalal SM, Law ME: Detection of newborn aneuploidy by interphase fluorescence in situ hybridization. Mayo Clin Proc 1997;72:705-710

2. Cassidy SB, Allanson JE: Management of Genetic Syndromes. Second edition. Hoboken, NJ, John Wiley and Sons, 2005, p 557

3. Sheets KB, Crissman BG, Feist CD, et al: Practice guidelines for communicating a prenatal or postnatal diagnosis of Down syndrome: recommendations of the national society of genetic counselors. J Genet Couns 2011;20:432-444

Method Description

This test is performed using probes for the centromere regions of chromosome X (DXZ1), Y (DYZ3), and 18 (D18Z1), and locus-specific probes for 13q14 and 21q22. For each probe set, 2 technologists each analyze 50 interphase nuclei (100 total). Aneuploidy of chromosomes 13, 18, 21, X, and Y is reported.(Unpublished Mayo method)

Day(s) Performed

Monday through Friday

Report Available

3 to 4 days

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

88271x2, 88291-DNA probe, each (first probe set), Interpretation and report

88271x2-DNA probe, each; each additional probe set (if appropriate)

88271x1-DNA probe, each; coverage for sets containing 3 probes (if appropriate)

88271x2-DNA probe, each; coverage for sets containing 4 probes (if appropriate)

88271x3-DNA probe, each; coverage for sets containing 5 probes (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)        

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NADF Newborn Aneuploidy Detection, FISH 57318-8


Result ID Test Result Name Result LOINC Value
51930 Result Summary 50397-9
51932 Interpretation 69965-2
54552 Result 57318-8
CG694 Reason for Referral 42349-1
51933 Specimen 31208-2
51934 Source 31208-2
51935 Method 85069-3
51931 Additional Information 48767-8
53862 Disclaimer 62364-5
51936 Released By 18771-6


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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)