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HelpEpic Test Code LAB2263 Chromosome Analysis, Congenital Disorders, Blood
Additional Codes
MML Code: CHRCB
Useful For
Diagnosis of congenital chromosome abnormalities, including aneuploidy, structural abnormalities, and balanced rearrangements
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.
This test is not appropriate for detecting acquired chromosome abnormalities. If this test is ordered with a reason for testing indicating a hematologic disorder, the test will be cancelled and CHRHB / Chromosome Analysis, Hematologic Disorders, Blood will be performed as the appropriate test.
A chromosomal microarray study (CMACB / Chromosomal Microarray, Congenital, Blood) is recommended as the first-tier test (rather than a congenital chromosome study) to detect clinically relevant gains or losses of chromosomal material for individuals with multiple anomalies not specific to well-delineated genetic syndromes, individuals with apparently nonsyndromic developmental delay or intellectual disability, and individuals with autism spectrum disorders.
Special Instructions
Method Name
Cell Culture with Mitogens followed by Chromosome Analysis
Reporting Name
Chromosomes, Congenital, BloodSpecimen Type
Whole bloodShipping 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
Submit only 1 of the following specimens:
Specimen Type: Whole blood
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. Label specimen as whole blood.
Specimen Type: Cord blood
Container/Tube: Green top (sodium heparin)
Specimen Volume: As much as possible
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. Label specimen as cord blood.
Blood Tube Draw Volume
Min 50% draw volume
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Ambient (preferred) | ||
| Refrigerated | |||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Chromosome analysis is appropriate for individuals with clinical features including infertility, multiple miscarriages, delayed puberty, ambiguous genitalia, amenorrhea, or individuals with clinical features suggestive of an aneuploidy syndrome, including Down syndrome, Turner syndrome, Klinefelter syndrome, Trisomy 13 syndrome, and Trisomy 18 syndrome.
A chromosomal microarray study (CMACB / Chromosomal Microarray, Congenital, Blood) is recommended as the first-tier test (rather than a congenital chromosome study) to detect clinically relevant gains or losses of chromosomal material for individuals with multiple anomalies not specific to well-delineated genetic syndromes, individuals with apparently nonsyndromic developmental delay or intellectual disability, and individuals with autism spectrum disorders. Chromosome analysis may be appropriate for this patient population if microarray has been performed with normal results. Some chromosome rearrangements are balanced (no gain or loss of material) and, therefore, not detectable by chromosomal microarray. In rare situations these rearrangements may interrupt gene functioning and have the potential to cause abnormal clinical features.
Limitations: A normal karyotype (46,XX or 46,XY with no apparent chromosome abnormality) does not eliminate the possibility of abnormal clinical features such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and environmental factors (ie, teratogen exposure). Chromosomal mosaicism may be missed due to statistical sampling error (rare) and subtle structural chromosome abnormalities can occasionally be missed.
Reference Values
An interpretive 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 abnormal results to the patient.
Cautions
This test is not appropriate for acquired hematologic disorders, including the following malignancies: chronic myelocytic leukemia, acute myelocytic leukemia, acute lymphocytic leukemia, chronic lymphocytic leukemia, lymphoma, and leukemia.
This test is not appropriate as a first-tier test for detecting gains or losses of chromosomal material for individuals with intellectual disability, developmental delay, autism, dysmorphic features, birth defects, behavior disorders, learning disability, or cognitive impairment.
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 blood 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
Day(s) Performed
Monday through Friday
Report Available
10 daysSpecimen Retention Time
4 weeksPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
88230, 88291- Tissue culture for Lymphocytes, Interpretation and report
88262 w/modifier 52-Chromosome analysis less than15 cells (if appropriate)
88262-Chromosome analysis with 15 to 20 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)
NY State Approved
YesForms
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: