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HelpTest Code LABCCSNP CONSTITUTIONAL CYTOGENETICS, SNP MICROARRAY
Specimen and Container/Tube
Peripheral blood: EDTA and NaHep (dark green top)
Chorionic villus: Call the lab at 773-702-6203 for custom made collection and transport media
Amniotic fluid: Call the lab at 773-702-6203 for collection and transport containers
Products of conception: Call the lab at 773-702-6203 for custom made collection and transport media
Volume
Peripheral blood: Preferred: 1-3 mL in EDTA tube and 1-3 mL of in NaHep tube. Minimum: 1-3 mL NaHep tube.
Chorionic villus: Preferred: >40 mg of villi devoid of blood clots and maternal decidua Minimum: 10 mg Amount needed by test: chromosome analysis: 15-20 mg; Aneuploidy FISH: 5 mg; SNP array (direct): 15-20 mg
Amniotic fluid: Preferred: >40ml fluid devoid of red blood cells or clots. Minimum: 30 mL
Amount needed by test: chromosome anlaysis: 10-15 mL, Aneuploidy FISH: 5 mL, AFP, CMV, Toxo, etc: 5 mL, SNP Array (direct): 15mL
Products of conception: Preferred: 50 mg of villi devoid of blood clots and maternal decidua; Minimum: 10 mg
Specimen Stability
Peripheral blood: Stable at room temperature up to 24 hours after collection.
Chorionic villus: Keep at room temperature if sample is delivered to the lab <24 hrs from collection. If transport delay is expected, keep at 4°C.
Amniotic fluid: Keep at room temperature if sample is delivered to the lab <24 hrs from collection. If transport delay is expected, keep at 4°C.
Products of conception: Keep at room temperature if sample is delivered to the lab <24 hrs from collection. If transport delay is expected, keep at 4°C.
Note: Prolonged transport to the laboratory diminishes cell viability and successful testing of all sample types.
Collection Instructions
UCMC Onsite Instructions
Prior to collection of Chorionic Villus, Amniotic Fluid and Products of conception specimens: Call Cytogenetics at 773-702-6203 for collection containers and media as needed.
DO NOT use AMBER TUBES for Amniotic Fluid. These can be toxic to fetal cells.
UCMC Offsite and UC MedLab Outreach Instructions
Prior to collection of Chorionic Villus, Amniotic Fluid and Products of conception specimens: Call Cytogenetics at 773-702-6203 for collection containers and media as needed.
Specimen Handling and Transport Instructions
UCMC Onsite Instructions
Peripheral blood can be tubed directly to Cytogenetics via tube station #345
CVS, Amniotic fluid and Products of Conception: Call Cytogenetics at 773-702-6203 immediately after collection for sample pick up. Prenantal samples cannot be delivered in the tube station.
UCMC Offsite and UC MedLab Outreach Instructions
Chorionic Villus and Amniotic Fluid specimens: Arrange for independent courier to deliver specimens in provided collection tubes DIRECTLY to the Cytogenetics lab in Hyde Park. Notify the Cytogenetics lab at 773-702-6203 that a sample is being sent.
Products of conception specimens: Send specimen in provided media cup per routine transport methods.
Rejection Criteria
Peripheral blood: Specimens received in the laboratory >48 hours after collection; samples in incorrect anticoagulant, clotted, or hemolyzed
Chorionic Villus: Specimens received >72 hours after collection
Amniotic Fluid: Specimens received >72 hours after collection
Products of Conception: Specimens fixed in formalin; Non-pregnancy tissue (at the discretion of the section director or supervisor); Specimens received in the laboratory >1 week after collection
Reference Values
Results are intepreted based on technical standards jointly published by the American College of American Genetics (ACMG) and the the Clinical Genome Resource (ClinGen).
Results reported with current recommendations of the International Standing Committee on Human Cytogenomic Nomenclature (ISCN).
Turnaround Time
Peripheral blood: up to 28 days
Chorionic villus: up to 21 days
Amniotic fluid: up to 14 days
Products of conception: up to 42 days
Please note: Turnaround times can vary based on lab staffing. For urgent needs and requests to expedite testing, please email #UCM-Cytogenetics-Lab, or CytogeneticsLab@uchicagomedicine.org
Clinical Indications
Indication for SNP array testing in the postnatal setting include: Individuals with developmental delay/intellectual disability (with or without dysmorphic
features), multiple congenital anomalies, autism spectrum disorder/pervasive developmental disorder, epilepsy/seizures, heart defects, family history of a chromosomal abnormality resulting in a genomic imbalance.
Indication for prenatal SNP array include: pregnancies at increased risk for fetal chromosome abnormality based on maternal age, abnormal noninvasive
prenatal testing (NIPT), abnormal multiple marker screening, or abnormal fetal ultrasound; clarification of ambiguous chromosome results; family history of genetic syndrome of unknown etiology.
Indication for SNP array testing of
products of conception include: pregnancy loss of unknown etiology; fetal anomalies; parental chromosome abnormality; clarification of ambiguous chromosomal
findings; detection of chromosome rearrangements; failiure of tissue to grow in culture.
Test Components
DNA Extraction
SNP Microarray
Interpretive Report
Methodology
SNP microarray includes 2.67 million markers for copy number (CN) analysis including approximately 750,000 SNP probes, and 1.9 million non-polymorphic probes for whole genome coverage.
CPT Codes
Peripheral blood: 81229
Chorionic Villus: 81229
Amniotic Fluid: 81229
Products of Conception: 81229
Ordering Notes
For questions about microarray testing email #UCM-Cytogenetics-Lab, or CytogeneticsLab@uchicagomedicine.org
Synonyms/Key Search Words
Microarray, SNP, gen hyb, aCGH, Gene, Whole Gene, CGH, CMA, Cytogenomic
Additional Information
SNP microarray Limitations: This test will not detect balanced translocations, low level mosaicism, point mutations and small insertion/deletions. It may raise concern but is not diagnostic for uniparental disomy (UPD).
Last Review Date
4/17/2025