Prenatal Tests

EGL Genetics offers both Cytogenetic and Molecular prenatal testing options. Molecular prenatal testing is performed by known mutation analysis with the exceptions of L1CAM, PKHD1, and TAR syndrome testing. In these cases, full gene sequence analysis or TAR syndrome panel testing can be performed on prenatal samples when indicated by ultrasound findings. EGL does not perform biochemical prenatal diagnosis.

Please call (855) 831-7447 to speak with a laboratory genetic counselor prior to ordering prenatal testing.

Prenatal Molecular Genetic CPT Codes

Informed Consent for Molecular Prenatal Genetic Testing 

Informed Consent for Prenatal Chromosomal Microarray Testing 

General Criteria

  1. A maternal blood sample must accompany the prenatal sample to test for maternal cell contamination (MCC). A paternal sample may also be required (see below).
  2. The indications for prenatal testing must be specified on the requisition.
  3. Amniocyte and chorionic villus samples are acceptable for direct analysis for many molecular tests. However, a culture must be started either by the referring laboratory or by EGL Genetics. Culturing samples for molecular tests performed at EGL incurs a charge and must be specifically ordered.
In addition to these general criteria, specific criteria must be followed depending on the type of testing being performed.

Chromosomal Microarray Testing

  1. Both maternal and paternal blood samples (sodium heparin and EDTA whole blood) are required. We perform maternal cell contamination studies and parental studies when indicated. Parental studies are necessary to determine inheritance for an imbalance of uncertain significance in the fetus.
  2. Indicate all relevant fetal findings on the test requisition and when possible, submit a copy of reports for abnormal ultrasounds and previous genetic testing.

Non-sequencing-based Testing

 (i.e. alpha-thalassemia, cystic fibrosis, myotonic dystrophy, sickle cell anemia, etc.)

  1. The carrier status of both parents must be documented* by molecular analysis and copies of the laboratory report must accompany the fetal sample. Prenatal testing will not be performed without this documentation.
  2. If molecular testing of the parents has not been performed, carrier testing of the parental samples will be performed by EGL and a charge will be incurred.
  3. With prior approval from a laboratory director, parental samples may be submitted for carrier testing concurrently with the prenatal sample to expedite testing.
*Hemoglobin electrophoresis is not sufficient to establish parental sickle cell carrier status. A molecular (DNA) test must be performed for BOTH parents.

Previously Identified Familial Mutations for Sequencing Tests

  1. An affected family member or known carrier(s) must be tested first. If testing was not performed through a CLIA-certified laboratory, confirmation studies of the index case will be required and charges will be incurred. A blood or DNA sample from a family member documented to carry the mutation(s) may be necessary if testing was not performed by EGL (for quality control purposes only).
  2. The parent(s) must have molecular testing for the familial mutation. If testing has previously been performed by a CLIA-certified laboratory outside EGL, a copy of the laboratory report must accompany the samples. If testing was not performed in a CLIA-certified laboratory, EGL will test the parent(s) and charges will be incurred.
  3. Both maternal and paternal blood or DNA samples are requested for quality control purposes.

Previously Identified Familial Mutations for Custom Sequencing Tests

EGL offers custom molecular diagnostic testing. This type of testing requires development and validation of the assay on an affected individual or obligate carrier BEFORE prenatal testing can be initiated. Therefore, the time required is longer than for other prenatal testing currently offered by the laboratory.
  1. Before prenatal testing can be initiated, an affected family member or known carrier(s) must be tested at EGL. A copy of the laboratory report identifying the mutation(s) must be provided.
  2. Both maternal and paternal blood or DNA samples are required for quality control purposes. All other criteria described in "Previously Identified Familial Mutations for Sequencing Tests" above applies.

In The Spotlight

Christin Collins

Dr. Collins is a board-certified molecular geneticist and a laboratory director for the Molecular Genetics Laboratory.

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