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HelpMayo Test ID CHRTI Chromosome Analysis, Skin Biopsy
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.
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.
Special Instructions
Method Name
Cell Culture followed by Chromosome Analysis
Reporting Name
Chromosomes, Skin BiopsySpecimen Type
TissueSpecimen 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.
Clinical Reference
1. McKinlay Gardner RJ, Amor DJ, eds. Gardner and Sutherland's Chromosome Abnormalities and Genetic Counseling, 5th ed. Oxford Monographs on Medical Genetics, 2018
2. Gersen S, Keagle M. The Principles of Clinical Cytogenetics. Springer; 2013
3. Azcona C, Bareille P, Stanhop R. Lesson of the week: Turner's syndrome mosaicisim in patients with a normal blood lymphocyte karyotype. BMJ. 1999;318:856-857
4. Woods CG, Bankier A, Curry J, et al. Asymmetry and skin pigmentary anomalies in chromosome mosaicism. J Med Genet. 1994;31(9):694-701
5. Ribeiro Noce T, de Pina-Neto JM, Happle R. Phylloid pattern of pigmentary disturbance in a case of complex mosaicism. Am J Med Genet. 2001;98(2):145-147
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 daysSpecimen Retention Time
4 weeksPerforming 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 |