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Test Code CHRTI Chromosome Analysis, Skin Biopsy

Useful For

Diagnosis of mosaic congenital chromosome abnormalities, including mosaic aneuploidy and mosaic structural abnormalities

 

Subsequent chromosome analysis when results from peripheral blood are inconclusive

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
_M15A Metaphases, 1-14 No, (Bill Only) No
_M19 Metaphases, 15-20 No, (Bill Only) No
_MG19 Metaphases, >20 No, (Bill Only) No
_KTG2 Karyotypes, >2 No, (Bill Only) No
_STAC Ag-Nor/CBL Stain No, (Bill Only) No

Testing Algorithm

This test includes a charge for cell culture of fresh specimens and professional interpretation of results. Analysis charges will be incurred for total work performed, and generally include 2 banded karyograms and the analysis of 20 metaphase cells. If no metaphase cells are available for analysis, no analysis charges will be incurred. If additional analysis work is required, additional charges may be incurred.

Method Name

Cell Culture followed by Chromosome Analysis

Reporting Name

Chromosomes, Skin Biopsy

Specimen Type

Tissue


Shipping Instructions


Advise Express Mail or equivalent if not on courier service.



Necessary Information


Provide a reason for testing 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.



Specimen Required


Specimen Type: Skin biopsy

Container/Tube: Sterile container with sterile RPMI transport media, Ringer's solution, or normal saline-RPMI transport media (T095-Petri dish is not needed for this test).

Specimen Volume: 4 mm diameter

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.


Specimen Minimum Volume

4 mm punch biopsy

Specimen Stability Information

Specimen Type Temperature Time Special Container
Tissue Refrigerated (preferred)
  Ambient 

Reject Due To

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

Clinical Information

Chromosomal abnormalities cause a wide range of disorders associated with birth defects and congenital diseases. Usually, the abnormalities can be demonstrated in peripheral blood, which is readily available. Chromosome analysis on skin fibroblasts may be indicated when the results from peripheral blood are inconclusive or in clinical circumstances such as suspected cases of chromosome mosaicism, confirmation of new chromosome disorders, or some dermatological disorders.

 

Subtle structural chromosomal anomalies can occasionally be missed.

 

Chromosomal mosaicism may be missed due to statistical sampling error (rare).

Reference Values

An interpretative report will be provided.

Interpretation

When interpreting results, the following factors need to be considered:

-Some chromosome abnormalities are balanced (no apparent gain or loss of genetic material) and may not be associated with birth defects. However, balanced abnormalities often cause infertility and, when inherited in an unbalanced fashion, may result in birth defects in the offspring.

-A normal karyotype (46,XX or 46,XY with no apparent chromosome abnormality) does not eliminate the possibility of birth defects such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and environmental factors (ie, teratogen exposure).

 

It is recommended that a qualified professional in Medical Genetics communicate all results to the patient.

Cautions

Interfering factors:

-Transport time should not exceed 2 days.

-Inadequate amount of fluid may not permit adequate analysis.

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

-Exposure of the specimen to temperature extremes (freezing or > 30° C) may kill cells and interfere with attempts to culture cells.

Method Description

TThe specimen is cut into small pieces and treated with enzymes. The tissue is then placed into tissue culture dishes with Chang and MEM-alpha-medium containing 10% fetal bovine serum and antibiotics to establish a fibroblast culture. The fibroblasts are exposed to ethidium bromide, colcemid, and hypotonic solution and fixed with glacial acetic acid and methanol. Metaphase preparations are routinely stained by G-banding, but other staining methods are frequently employed as needed. At least 20 metaphases are examined. Minimal evidence for the presence of an abnormality is defined as 2 or more metaphases with the same structural abnormality or chromosome gain (trisomy), or 3 or more metaphases lacking the same chromosome. Five to 10 metaphases are captured using a computer-based imaging system and karyograms are prepared from 2 or more representative metaphases.(Arsham MS, Barch MJ, Lawce HJ, eds. The AGT Cytogenetics Laboratory Manual. 4th ed. John Wiley and Sons; 2017)

Day(s) Performed

Monday through Friday

Report Available

23 to 24 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

88233, 88291- Tissue culture for skin/biopsy, Interpretation and report

88262 w/modifier 52-Chromosome analysis less than 15 cells(if appropriate)

88262-Chromosome analysis with 15 to 120 cells (if appropriate)

88262, 88285-Chromosome analysis with greater than 20 cells (if appropriate)

88280-Chromosome analysis, greater than 2 karyotypes (if appropriate)

88283-Additional specialized banding technique (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CHRTI Chromosomes, Skin Biopsy 62353-8

 

Result ID Test Result Name Result LOINC Value
52311 Result Summary 50397-9
52313 Interpretation 69965-2
52312 Result 82939-0
CG768 Reason for Referral 42349-1
52314 Specimen 31208-2
52315 Source 31208-2
52317 Method 85069-3
52316 Banding Method 62359-5
54642 Additional Information 48767-8
52318 Released By 18771-6