LabCorp and its Specialty Testing Group, a fully integrated portfolio of specialty and esoteric testing laboratories.
For prenatal/fetal testing only.
Testing referred to Integrated Genetics. To speak to a laboratory genetic coordinator before collecting specimens, LabCorp Clients, call 800-345-4363; Integrated Genetics clients, call 800-848-4436.
In some circumstances, specimens from other family members may be required. All prenatal specimens (including cord blood) must be accompanied by a maternal blood or mouthwash specimen for analysis of the specimen for possible maternal cell contamination. Cultures are required for prenatal SMA testing.
Cultured amniotic fluid, or cultured chorionic villus (CVS) cells are required for testing.
Direct specimen can be submitted but a culture fee may be included. Submission of maternal blood is required for analysis of maternal cell contamination (MCC). MCC should be ordered on a separate requisition using test code 511402, Maternal Cell Contamination. Cultures are required for prenatal SMA testing.
Amniotic fluid: One T-25 flask of confluent cells. CVS: One T-25 flask of confluent cells. If cultured at another facility please maintain back-up cultures.
Amniotic fluid: T-25 flasks
CVS: T-25 flasks
Amniotic fluid: Discard first 2 mL; then 15 mL amniotic fluid in 15 mL orange-top polypropylene tube. If cultured at another facility: 1 T-25 flask of confluent cells.
Maintain specimen at room temperature.
Frozen or hemolyzed specimen; quantity not sufficient for analysis
Prenatal diagnosis for at-risk pregnancies, when both parents are carriers or when severe joint contractures are found on fetal ultrasound.
If prenatal diagnosis testing indicated an affected fetus (a 0 SMN1 copy number result), testing will reflex to SMN2 copy number analysis. SMN2, an adjacent gene to SMN1, also encodes low levels of SMN protein. Therefore, an increased SMN2 copy number (3+) may reduce disease severity among affected patients.
This copy number analysis does not detect carriers of SMA as a result of either two (or very rarely three) copies of the SMN1 gene on one chromosome False-positive results or false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, erroneous representation of family relationships, or contamination of a fetal sample with maternal cells.
After DNA is isolated, exon 7 of the SMN1 gene and internal standard reference genes are amplified by real-time polymerase chain reaction (PCR). A mathematical algorithm calculates SMN1 copy numbers of 0, 1, 2 or 3 with statistical confidence. To rule out the presence of sequence variants that could interfere with analysis and interpretation, sequence analysis of primer and probe binding sites is performed for postnatal samples with one copy of SMN1 and for all fetal samples. Reflex testing to SMN2 copy number analysis is performed for affected fetus with 0 copies of SMN1.
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|452140||Prenatal SMN1 Copy Number||450001||Genetic Counselor:||89993-0|
|452140||Prenatal SMN1 Copy Number||450002||Client Specimen ID:||48767-8|
|452140||Prenatal SMN1 Copy Number||450003||Specimen Type:||31208-2|
|452140||Prenatal SMN1 Copy Number||450004||Specimen(s) Received:||74384-9|
|452140||Prenatal SMN1 Copy Number||450005||Clinical Data:||42349-1|
|452140||Prenatal SMN1 Copy Number||450006||Ethnicity:||42784-9|
|452140||Prenatal SMN1 Copy Number||450007||SMA Results:||41053-0|
|452140||Prenatal SMN1 Copy Number||450008||SMA Interpretation:||35462-1|
|452140||Prenatal SMN1 Copy Number||450009||Comments:||48767-8|
|452140||Prenatal SMN1 Copy Number||450111||Carrier Detection Rate:||N/A|
|452140||Prenatal SMN1 Copy Number||450011||Method/Limitations:||49549-9|
|452140||Prenatal SMN1 Copy Number||450012||References:||69549-4|
|452140||Prenatal SMN1 Copy Number||450013||Disclaimer:||62364-5|
|452140||Prenatal SMN1 Copy Number||450014||Electronically Signed by:||N/A|
|452140||Prenatal SMN1 Copy Number||450015||SMN1 Copy Number Analysis PDF||51969-4|
|452140||Prenatal SMN1 Copy Number||452141||SMA Results:||41053-0|
|Reflex Table for SMA Results:|
|Order Code||Order Name||Result Code||Result Name||UofM||Result LOINC|
|Reflex 1||451790||SMN2 Copy Number Reflex||451788||SMN2 Copy Number Reflex||54449-4|
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