Parental Testing for Prenatal Cases Tested by the Signature PrenatalChip®
Signature Genomic Laboratories recommends testing of parental samples in cases in which the patient is found to have an abnormal test result. Analysis of parental samples determines whether an abnormality is familial or de novo, and can provide clarification of interpretation and clinical relevance of the patient’s results.
Please see Signature Genomic Laboratories’ Prenatal Diagnosis Services for details.
On occasion, parental blood samples may be needed to clarify a microarray result discovered in the prenatal sample. In most cases, this cannot be predicted in advance of PrenatalChip® analysis. To expedite this process and provide rapid and comprehensive interpretation of prenatal test results, Signature Genomic Laboratories recommends that parental blood samples are submitted with the prenatal sample. For each parent, please submit two tubes, each with 3-5 cc whole blood, one sodium heparin (NaHep) green-top tube and one EDTA purple-top tube and include requisition forms as instructed below.
Signature Genomics does not charge for parental analysis in cases in which parental samples are needed to interpret a microarray finding of unclear clinical relevance in the fetus. Signature Genomics charges a reduced price for parental analysis in cases in which parental testing is medically indicated (for example, a parent with similar clinical features to the fetus found to have a microdeletion or microduplication that is known or suspected to have clinical relevance) or testing is recommended as standard of care for estimation of recurrence risks and accurate genetic counseling (for example, parental testing for a balanced chromosomal rearrangement). In all abnormal microarray cases for which parental testing is offered for a charge, the ordering clinician will be notified and given the opportunity to consult with the parents prior to testing so that they have the option to decide to proceed or not with analysis. The cost of appropriate parental analyses and payment options will be discussed with the clinician at that time.
Please note that analysis of parental samples has the potential to reveal unexpected DNA dosage alterations that may have clinical significance for the parent. Parental samples will be held until prenatal test results are complete. If prenatal testing is normal, parental samples will not be tested and will be discarded according to established guidelines.
Parental samples may be submitted in advance of the fetal sample; however, if prenatal testing is subsequently cancelled or not pursued, there will be a DNA extraction charge for each parental sample processed (see Signature Test Cancellation Policy).
Genetic counseling is strongly recommended prior to prenatal testing so that parents understand the implications of parental testing.
Signature PrenatalChip® Requisition Form
Instructions for Submitting Parental Samples
A separate requisition form must be completed for each parental sample submitted. Below are specific instructions to complete the Signature PrenatalChip® Requisition Form to expedite processing of parental samples. Please call the Laboratory with questions. Incorrect or missing information may delay sample processing.
Instructions:
- Physician Signature
- Please provide physician or health care provider signature to acknowledge that the benefits and limitations of microarray testing have been discussed with each parent.
- Patient Information
- Please provide parent name, demographic information and gender. Please submit a separate requisition form for each parent.
- Referring Physician
- Please provide the name and contact information of the ordering physician and the counselor/contact to whom results should be called.
- Billing Information
- Please check the Parental Sample box. Please note that Signature Genomics charges a reduced price in cases for which parental testing is medically indicated or recommended as standard of care for estimation of recurrence risks and genetic counseling. Signature Genomics does not charge for analysis of parental samples in cases for which parental samples are needed to interpret the child's array finding of unclear clinical significance.
- Testing Information
- Please check the Parental Study box and provide the name and SGL# (Signature Genomics Laboratory accession number) of the index case (this is typically the mother's name for prenatal samples). No further information is required in this section.
- Sample Information
- Please indicate sample type.
How to Submit a Prenatal Sample
For step-by-step instructions on submitting a prenatal sample, please visit our How To Submit a Prenatal Sample page.