Spinal Muscular Atrophy (SMA), Fetus

Test Code

91619

CPT Codes
81329

Physician Attestation of Informed Consent

This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.

Preferred Specimen

10 mL amniotic fluid collected in a sterile leak-proof container

Minimum Volume

10 mL amniotic fluid • 10 mg chorionic villi

Other Acceptable Specimens

10 mg chorionic villus in sterile T-25 flask (x2)

Instructions

1) Please call 1-866-GENE-INFO (1-866-436-3463) prior to submission
2) Parents must be documented carriers of SMA
3) It is strongly recommended that Maternal Cell Contamination Study, STR Analysis be ordered in conjunction with fetal testing. A separate tube of maternal blood (EDTA) is required for this test.

Do not hold cells; forward to laboratory when cells arrive.

Amniotic fluid (acceptable): Normal collection procedure. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Amniocyte or Chorionic Villus (CVS) culture (acceptable): Two sterile T25 flasks, filled with culture medium. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Dissected Chorionic Villus (CVS) biopsy (acceptable): 10-20 mg dissected chorionic villi collected in sterile tube, filled with sterile culture medium. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Do not reject. Forward to performing laboratory for evaluation of sample.

Methodology
Allele Specific Real-Time Polymerase Chain Reaction, ddCt Method

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Daily; Report available: 7 days

Clinical Significance

Spinal Muscular Atrophy (SMA), Fetus assesses fetal SMN1 and SMN2 copy number. This test will determine whether a fetus is affected by SMA, caused by deletions of at least exon 7 of the SMN1 gene. It does not determine the presence or absence of a sequence variant in the SMN1 gene. In addition, it does not assess risk for 2+0 carrier status.

SMA is the second most common lethal autosomal recessive disease and is a family of disorders that is characterized by progressive muscle weakness due to loss of anterior horn cells. A loss of at least exon 7 in the SMN1 gene, located on chromosome 5q, causes 95% of SMA. SMN2 genes produce a protein identical to that of SMN1 gene, but in a reduced (10-20%) amount. As a result, the number of copies of SMN2 has been shown to influence the severity of the disease.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.