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
Chromosome studies are recommended to detect balanced rearrangements that will not be detected by the array. For chromosome analysis, please order Chromosome Analysis, Amniotic Fluid [052040] or Chromosome Analysis, Chorionic Villi Biopsy [510988]. Concurrent maternal contamination (MCC) studies (Maternal Cell Contamination [511402]) are recommended. 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 or prior cell-free DNA/NIPT studies have been performed, please include copy of the report. If the specimen does not meet minimum DNA/fresh tissue specimen quality and quantity requirements, array testing will be performed on cultured material and the 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
Amniotic fluid (AMD) or chorionic villus (CVS)
Volume
Amniotic fluid, 15-20 mL (20-30 mL for early amniocentesis); or chorionic villi, 20-30 mg
Minimum Volume
Amniotic fluid, 12 mL or chorionic villi, 10 mg
Container
Amniotic fluid: sterile plastic conical tube
Chorionic villi: transport tube (a sterile specimen container with transport medium) is available from Labcorp; please call customer service at 800-345-4363
Collection Instructions
Amniotic fluid: 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. Request form is completed and accompanies specimen and miscellaneous slip to the laboratory. Rubber stopper and/or frozen specimen cannot be processed.
Chorionic villi: 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 (NaCl 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. No villi, frozen specimen and specimen in fix cannot be processed.
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 |