Cytogenetics CMA Prenatal
| Epic code: | CYT70 & CYT71 |
Shivanand R. Patil Cytogenetics & Molecular Laboratory
Department of Pediatrics
W-101 GH
356-3877 (Laboratory)
Department of Pediatrics
W-101 GH
356-3877 (Laboratory)
Specimen(s):
Amniotic Fluid
Specimen
Instructions:
Collection Instructions for Amniotic Fluid:
Collect 20-30 ml amniotic fluid in a sterile container (15cc tubes available from lab upon request).
Discard the first 2 mL of amniotic fluid.
Store at room temperature and transport to laboratory as soon as possible (W101 General Hospital, tube station 113)
Specimens collected outside of laboratory business hours (8AM-5PM Monday-Friday) send to specimen control (6240 RCP, tube station 160)
Maternal cell contamination (MCC) studies will be performed if a maternal blood sample is received
Collect 20-30 ml amniotic fluid in a sterile container (15cc tubes available from lab upon request).
Discard the first 2 mL of amniotic fluid.
Store at room temperature and transport to laboratory as soon as possible (W101 General Hospital, tube station 113)
Specimens collected outside of laboratory business hours (8AM-5PM Monday-Friday) send to specimen control (6240 RCP, tube station 160)
Maternal cell contamination (MCC) studies will be performed if a maternal blood sample is received
Minimum:
20-30 mL Amniotic Fluid
Minimum: 10 mL
For MCC collect 5-10 ml maternal blood in an EDTA (purple top) tube
Minimum: 10 mL
For MCC collect 5-10 ml maternal blood in an EDTA (purple top) tube
Rejection Criteria:
Bloody specimens are undesirable.
Turn Around
Time:
within 10 days upon receipt at reference laboratory
Reference Range:
Normal male results are described as: arr(X,Y)x1,(1-22)x2. Normal female results are described as: arr(X,1-22)x2.
CPT Code:
81229, 88291
The GDA+Cyto array is an ultra-high density genome wide DNA array designed to measure DNA copy number gains and losses associated with chromosomal imbalances. This array also provides genotyping information, enabling detection of regions of homozygosity (ROH). The array has high density coverage for each chromosome to detect chromosome rearrangements such as deletions and duplications. The array is a commercial platform and contains 1.8 million markers.
Currently, this test detects gains and losses of chromosome regions in the genome, and large areas of ROH. Large segments of ROH when contained to a single chromosome may be suggestive of uniparental disomy (UPD). Large segments of ROH when distributed across the genome can indicate identity by descent or parental consanguinity. A normal array result does not exclude sequence variants in any genes represented on the microarray and does not exclude balanced rearrangements (such as translocations or inversion), low-level mosaicism, or epigenetic events (such as imprinting mutations). Copy number changes that are classified as either benign or likely benign are not reported. Additional testing may be appropriate for certain syndromes or clinical conditions when the array results are normal.
Reportable range:
All copy number variants, within the limit of detection, classified as pathogenic or likely pathogenic will be reported regardless of size. Deletions of uncertain significance >1 MB and duplications of uncertain significance >2 MB which contain at least one protein coding gene will also be included in the report. Regions of homozygosity >5 MB contained to a single chromosome with known imprinted regions (chromosomes 6, 7, 11, 14, 15, 20) and genome wide regions of homozygosity >5% will be reported.
After Hours Pager: 5525