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Prenatal Diagnosis for Known Familial Mutations in X-Linked Disorders
For X-linked disorders, testing of a positive control is an essential aspect of accurate prenatal diagnosis.
If the proband was diagnosed at GeneDx, subsequent prenatal diagnosis usually can be completed with a 2-week turnaround. Carrier Testing on the mother of the pregnancy is optional. During prenatal diagnosis, GeneDx must have on hand a specimen from an affected male family member and a maternal specimen for MCC testing. If such specimens were tested more than 6 months previously, fresh specimens are requested from the mother and if possible the male control.
If the proband was tested in another CLIA laboratory or a research laboratory, please follow the steps in the corresponding column below. If a Mutation Confirmation or Carrier Test (obligate carrier or accompanied by a positive control) is not ordered in advance, the 2-week TAT for prenatal diagnosis does not apply. If outside testing was done in a research laboratory, advance Mutation Confirmation is mandatory.
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Previous Testing Performed By
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GeneDx
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Other CLIA Laboratory
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Research Laboratory
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STEPS for X-Linked Disorders
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1
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Submit the outside molecular lab results to GeneDx for review and pre-approval
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Not necessary
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Required
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Required
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2
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Order Mutation Confirmation (#9001 below) on a positive relative, 1 month or more in advance.
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Not necessary
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Optional; otherwise send as an internal control for Step 3 or 4; no separate report
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Required
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3
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If the mother elects carrier testing, order Carrier Testing (#9011 below). A positive control specimen is required, if not already sent.
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Optional
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Optional
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Optional
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4
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Submit a fetal specimen for prenatal diagnosis (#902 below). Specimens that must accompany the fetal specimen if not sent within 6 months are Maternal (for MCC testing) and Positive Control.
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TAT will be 2 weeks in most cases
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TAT will be 2 weeks in most cases, if Step 2 already complete
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TAT will be 2 weeks in most cases, if Step 2 already complete
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9001
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Mutation Confirmation for research results, one mutation. $350. For independent confirmation send fresh blood, 1-3 mL in EDTA, or a GeneDx buccal kit. If a fresh specimen is not available, 5 mcg stored DNA will be accepted. An individual report is provided. TAT 4 weeks. For CPT codes see the Information Sheet under Mutation Confirmation on the main web menu.
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9011
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Carrier Testing for one familial mutation. $350. Specimens can be 1-3 mL EDTA blood, a GeneDx buccal kit, or 5 mcg DNA. An individual report is provided. TAT 4 weeks. For CPT codes see the Information Sheets under Carrier Test on the main web menu.
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902
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Prenatal diagnosis for one or two mutations. $2000. Includes duplicate analysis, testing for maternal cell contamination, and internal control tests. Specimens include 10 mg CVS, 10 mL AF if >15 wks, 2 confluent CV or AF culture flasks. TAT is usually 2 weeks if positive controls have been successfully tested in advance.
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For specimen requirements click here to go to Amnio/CVS/Cultures under Send a Specimen
Click here for prenatal diagnosis CPT codes and pricing
