Prenatal diagnosis of chromosome abnormalities, including aneuploidy (ie, trisomy or monosomy) and balanced rearrangements
Cultures from this specimen will be discarded 10 days after all cytogenetic test results have been reported. If further testing is desired, call the laboratory at 507-284-1668.
| Test Id | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| _ML15 | Metaphases, <15 | No, (Bill Only) | No |
| _M15 | Metaphases, 15 | No, (Bill Only) | No |
| _MG14 | Metaphases, >15 | No, (Bill Only) | No |
| _COL1 | Colonies, 1-5 | No, (Bill Only) | No |
| _COL6 | Colonies, 6+ | No, (Bill Only) | No |
| _KTG1 | Karyotypes, >1 | No, (Bill Only) | No |
| _STAC | Ag-Nor/CBL Stain | No, (Bill Only) | No |
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.
Cell Culture Followed by Chromosome Analysis
Amniotic Fluid, Chromosome Analysis
Chromosome Analysis, Amniotic Fluid
Karyotype, Amniotic Fluid
Prenatal Chromosomes, Amniotic Fluid
Fetal Aneuploidy
Fetal Chromosome Analysis
DNA Screening for Fetal Aneuploidy
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.
Amniotic Fld
Portions of the specimen may be used for other tests such as measuring markers for neural tube defects (eg, AFPA / Alpha-Fetoprotein, Amniotic Fluid), molecular genetic testing, biochemical testing, and FISH testing (including PADF / Prenatal Aneuploidy Detection, FISH). If additional molecular genetic or biochemical genetic testing is needed, order CULAF / Amniotic Fluid Culture/Genetic Testing so that amniocyte cultures may be set up specifically for the use in these tests.
Advise Express Mail or equivalent if not on courier service.
Provide a reason for referral and gestational age with each specimen, and verify the specimen source. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
| Question ID | Description | Answers |
|---|---|---|
| CG765 | Reason for Referral | |
| CG766 | Specimen |
Supplies: Refrigerate/Ambient Shipping Box, 5 lb (T329)
Specimen Type: Amniotic fluid
Submission Container/Tube: Centrifuge tube
Specimen Volume: 20-25 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.
2. Discard the first 2 mL of amniotic fluid.
3. Place the tubes in a Refrigerate/Ambient Shipping Box, 5 lb (T329).
4. Fill remaining space with packing material.
Additional Information:
1. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
2. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
3. Bloody specimens are undesirable.
Supplies: Refrigerate/Ambient Shipping Box, 5 lb (T329)
Specimen Type: Fetal body fluid
Container/Tube: Sterile tube
Specimen Volume: Entire specimen
Collection Instructions:
1. Place the tubes in a Refrigerate/Ambient Shipping Box, 5 lb (T329).
2. Fill remaining space with packing material.
Additional Information:
1. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
2. Clearly indicate on tube and paperwork that specimen is fetal body fluid.
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:
Amniotic Fluid: 12 mL; Fetal Body Fluid: NA; If ordering in conjunction with other testing: If ordered with PADF: 14 mL, with CMAP: 24 mL, with PADF and CMAP: 26 mL
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Amniotic Fld | Refrigerated (preferred) | ||
| Ambient | |||
Prenatal diagnosis of chromosome abnormalities, including aneuploidy (ie, trisomy or monosomy) and balanced rearrangements
Cultures from this specimen will be discarded 10 days after all cytogenetic test results have been reported. If further testing is desired, call the laboratory at 507-284-1668.
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.
Chromosome analysis for prenatal diagnosis is appropriate in pregnancies with abnormal maternal screening, advanced maternal age, and features suggestive of or concerns for aneuploidy syndromes, including Down syndrome, Turner syndrome, Klinefelter syndrome, trisomy 13 syndrome, and trisomy 18 syndrome.
Chromosomal abnormalities are the cause of a wide range of disorders associated with birth defects and congenital diseases. Many of these disorders can be diagnosed prenatally by analysis of amniocytes. This method permits diagnosis of chromosome abnormalities during the second trimester of pregnancy or later.
A chromosomal microarray (CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling) is recommended, rather than chromosomal analysis, to detect clinically relevant gains or losses of chromosomal material in pregnancies with 1 or more major structural abnormalities. Chromosomal microarray can also be considered, rather than chromosome analysis, for patients undergoing invasive prenatal diagnostic testing with a structurally normal fetus.
An interpretative report will be provided.
Cytogenetic studies on amniotic fluid are considered nearly 100% accurate for the detection of large fetal chromosome abnormalities. However, subtle or cryptic abnormalities involving microdeletions usually can be detected only with the use of targeted FISH testing.
Approximately 3% of amniotic fluid specimens analyzed are found to have chromosome abnormalities. Some of these chromosome abnormalities are balanced and may not be associated with birth defects.
A normal karyotype does not rule out the possibility of birth defects, such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and other environmental factors (ie, teratogen exposure). For these reasons, clinicians should inform their patients of the technical limitations of chromosome analysis prior to performing the amniocentesis.
It is recommended that a qualified professional in Medical Genetics communicate all results to the patient.
Interfering factors:
-Improper syringes or transport vessels may be unsuitable to amniotic cells. Amniotic fluid should not be exposed to the syringe plunger tip for longer than a few seconds and fluid should be transferred to a transport (centrifuge) tube as soon as possible following collection.
-Transport time should not exceed 2 days.
-A bloody specimen may interfere with attempts to culture cells and contamination by maternal cells may cause interpretive problems.
-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 degrees C) may kill cells and severely interferes with attempts to culture cells.
1. American College of Obstetricians and Gynecologists Committee on Genetics: Committee Opinion No. 581: the use of chromosomal microarray analysis in prenatal diagnosis. Obstet Gynecol 2013;122:1374-1377
2. Society for Maternal-Fetal Medicine (SMFM): The use of chromosomal microarray for prenatal diagnosis. Am J Obstet Gynecol. 2016;215:B2-B9
3. Committee Opinion, 640: Cell-free DNA screening for fetal aneuploidy. American College of Obstetricians and Gynecologists Committee on Genetics. Obstet Gynecol 2015;123:e31-e37
4. Wilson KL, Czerwinski JL, Hoskovec JM, et al: NSGC practice guideline: prenatal screening and diagnostic testing options for chromosome aneuploidy. J Genet Couns 2013;22:4-15
The specimen is centrifuged and the cell pellet is mixed with culture media, then split into 6 primary culture dishes and a T-flask to establish cultures. Cells are harvested after 5 to 7 days. In the harvest process, the cells are exposed to ethidium bromide, colcemid, and hypotonic solution, and fixed with glacial acetic acid and methanol. Metaphase cells are dropped onto microscope slides and are routinely stained by G-banding, but other staining methods may be employed as needed. Fifteen metaphases from 15 colonies and 3 or more primary cultures usually are examined. In cases where true mosaicism is suspected, up to 30 colonies and up to 6 primary cultures may be analyzed. Minimal evidence for the presence of an abnormality is defined as 2 or more metaphases with the same structural abnormality, chromosome gain (trisomy), or 3 or more metaphases lacking the same chromosome. Five or more digitized images of metaphases are stored in computer-based imaging systems and karyograms are prepared from 2 or more representative metaphases.(Chang HC, Jones OW: Amniocentesis: cell culture of human amniotic fluid in a hormone supplement. Cold Springs Harb Conf Cell Prolif 1982;9:1187-1192; Hsu LY, Perlis TE: United States survey on chromosome mosaicism and pseudomosaicism in prenatal diagnosis. Prenat Diagn 1984;4:97-130; Peakman DC, Moreton MF, Corn BJ, Robinson A: Chromosomal mosaicism in amniotic fluid cell cultures. Am J Hum Genet 1979;31:149-155; Spurbeck JL, Carlson RO, Allen JE, Dewald GW: Culturing and robotic harvesting of bone marrow, lymph nodes, peripheral blood, fibroblasts, and solid tumors with in situ techniques. Cancer Genet Cytogenet 1988;32:59-66)
Monday through Friday
This test was developed, and its performance characteristics 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.
88235, 88291-Tissue culture for amniotic fluid or chorionic villus cells, Interpretation and report
88269 w/modifier 52-Chromosome analysis, in situ for amniotic fluid cells, <6 colonies, 1 karyotype with banding (if appropriate)
88269-Chromosome analysis, in situ for amniotic fluid cells, 6 or greater colonies, 1 karyotype with banding (if appropriate)
88267, 88285-Chromosome analysis, amniotic fluid or chorionic villus, greater than 15 cells, 1 karyotype with banding (if appropriate)
88267 w/modifier 52-Chromosome analysis, amniotic fluid or chorionic villus, <15 cells, 1 karyotype with banding (if appropriate)
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| CHRAF | Chromosomes, Amniotic Fluid | 62351-2 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 52297 | Result Summary | 50397-9 |
| 52299 | Interpretation | 69965-2 |
| 52298 | Result | 82939-0 |
| CG765 | Reason for Referral | 42349-1 |
| CG766 | Specimen | 31208-2 |
| 52300 | Source | 31208-2 |
| 52302 | Method | 85069-3 |
| 52301 | Banding Method | 62359-5 |
| 54640 | Additional Information | 48767-8 |
| 52303 | Released By | 18771-6 |