Reference Interval:
By report
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| Interpretive Data: |
Background Information for RhD Antigen (RhD) Genotyping:
Characteristics: Fetal or neonatal erythroblastosis and hydrops.
Incidence of Rhd negative genotype: 15% Caucasians, 5% African Americans, less than 1% Asians
Inheritance: Autosomal recessive
Cause: Maternal-fetal Rh D antigen incompatibility
Methods: Determine the presence of the RHD exons 5, 7, and a 37 base pair insertion in the intron 3/exon 4 boundary by PCR and fluorescence monitoring.
Allelic height ratios are used to determine the number of copies of RHD as compared to RHCE.
Limitations: Bloody amniotic fluid specimens may give false-negative results because of maternal cell contamination; specificity may be compromised by mutations in primer sites or those outside the RHD exons examined; fetuses predicted to be unaffected should continue to be monitored by noninvasive means.
Analytic Sensitivity and Specificity: Greater than 99%
Clinical Sensitivity: Greater than 98%
For quality assurance purposes, ARUP Laboratories will confirm the above result at no charge following delivery. Order Confirmation of Fetal Testing and include a copy of the original fetal report (or the mother's name and date of birth) with the test submission. Please contact an ARUP genetic counselor at (800) 242-2787 extension 2141 prior to specimen submission.
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
Refer to Statement C under Testing Information at http://www.aruplab.com.
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| Note: |
For Amniotic Specimens: For the Delta OD 450 nm, refer to Amniotic Bilirubin Scan (0080276). Whole blood is acceptable for paternal specimens.
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| CPT Code(s): |
83891 Isolation; 83898 x3 Amplification; 83896 x6 Nucleic acid probes; 83912 Interpretation and report Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders.
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Cross References: |
RHD Gene (RhD Antigen (RhD) Genotyping)
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