Test Details
Methodology
SNP microarray analysis is performed using the Cytoscan® HD Accel platform, which uses more than 743,130 SNP probes and 2,029,441 NPCN probes with a median spacing of 0.818 kb.
Result Turnaround Time
10 - 21 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test detects chromosomal imbalance that could be associated with developmental delay/congenital anomalies. It provides detection of possible uniparental disomy of any chromosome, the percentage and location of homozygosity, including the degree of identity by descent.
Special Instructions
For current chromosome analysis, please order Chromosome Analysis, Amniotic Fluid [052040] or Chromosome Analysis, Chorionic Villi Biopsy [510988]. Chromosome studies are recommended to detect balanced rearrangements that will not be detected by the array.
Pertinent medical findings must accompany the test request form. A complete Informed Consent and Prenatal Chromosome SNP Microarray Questionnaire should accompany specimens. Call 800-345-4363 to request the Informed Consent and Questionnaire form. If a chromosome study has been performed, it is recommended that it be included with sample submission. If prior Cell-free DNA/NIPT studies have been performed, include copy of the report. Concurrent maternal contamination (MCC) studies (Maternal Cell Contamination [511402]) are recommended. If the specimen does not meet minimum DNA/fresh tissue specimen quality and quantity requirements (less than 10 mL of amniotic fluid or DNA quantity less than 20 ng/uL); bloody sample; less than 10 mg CVS) array testing will be performed on cultured material and test number will be updated to SNP Microarray−Prenatal (Reveal®) [510100]. If cultures are needed and performed by Labcorp, additional days will be required to complete testing. A delay notification will be sent to the client if cultures are necessary. If cultured flasks are submitted under this test number, the test number will be changed to 510100.
Limitations
This SNP assay does not detect balanced rearrangements, low-level mosaicism (<10%), marker chromosomes that only contain heterochromatin or tetraploidy.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Specimen Requirements
Specimen
A minimum of 10 mL plus additional of amniotic fluid for direct array only and GA is >17+ weeks. Minimum 15 mL plus additional for backup for amniotic fluid for direct array only and GA is 15-16.9 weeks.
If ordered concurrently for chromosomes, a minimum of 25 mL of amniotic fluid is required. Fetal sex by ultrasound is required. Please submit maternal blood (sodium heparin or EDTA) for maternal cell contamination (MCC) studies.
CVS: 15 mg or greater
Volume
10-15 mL amniotic fluid for direct depending on GA and 25 mL for concurrent array and chromosomes; 10 mg CVS for direct and 25 mg for concurrent array and chromosomes
Minimum Volume
10 mL plus additional for backup for amniotic fluid if direct only and GA is > 17+ weeks; minimum 15 mL plus additional for backup for amniotic fluid if direct only and GA is 15-16.9 weeks
CVS: 10 mg plus additional for backup if direct only
Container
Sterile plastic conical tube for amniotic fluid. CVS transport tube (a sterile specimen container with transport medium) is available from Labcorp; please call customer service at 800-345-4363.
Collection Instructions
Discard first 2 mL of fluid aspirated to avoid maternal cell contamination. Specimen is collected in a 20 mL sterile syringe and transferred aseptically to sterile tubes to be transported to Labcorp.
Specimen is collected in syringe (transabdominal) or catheter (transcervical) and transferred by flushing with the media from the sterile container back into it. After collecting the specimen, wash with sterile saline solution (sodium chloride 0.95%) containing sodium heparin (two to three drops of sodium heparin in 10 mL of saline). Carefully transfer the specimen into the CVS transport tube using a sterile Pasteur pipette or a sterile fine needle forceps. Be sure to fill transport tubes completely with media. Samples from twin (multiple) pregnancies should be appropriately labeled and placed in separate transport containers with a separate request form for each twin.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Upon receipt, suitability of specimen will be determined by the Cytogenetics laboratory.
References
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 510200 | Direct Prenatal SNP CMA | 510103 | Specimen Type | 31208-2 | ||
| 510200 | Direct Prenatal SNP CMA | 510104 | # of Genotyping Targets | N/A | ||
| 510200 | Direct Prenatal SNP CMA | 510105 | Array Type | N/A | ||
| 510200 | Direct Prenatal SNP CMA | 510106 | Diagnosis | 48000-4 | ||
| 510200 | Direct Prenatal SNP CMA | 510107 | Interpretation | 62365-2 | ||
| 510200 | Direct Prenatal SNP CMA | 510108 | Director Review | 48672-0 | ||
| 510200 | Direct Prenatal SNP CMA | 512123 | 11502-2 | |||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510103 | |||||
| Result Code Name | Specimen Type | |||||
| UofM | ||||||
| Result LOINC | 31208-2 | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510104 | |||||
| Result Code Name | # of Genotyping Targets | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510105 | |||||
| Result Code Name | Array Type | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510106 | |||||
| Result Code Name | Diagnosis | |||||
| UofM | ||||||
| Result LOINC | 48000-4 | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510107 | |||||
| Result Code Name | Interpretation | |||||
| UofM | ||||||
| Result LOINC | 62365-2 | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 510108 | |||||
| Result Code Name | Director Review | |||||
| UofM | ||||||
| Result LOINC | 48672-0 | |||||
| Order Code | 510200 | |||||
| Order Code Name | Direct Prenatal SNP CMA | |||||
| Order Loinc | ||||||
| Result Code | 512123 | |||||
| Result Code Name | ||||||
| UofM | ||||||
| Result LOINC | 11502-2 |