RhE/e (RHCE) Antigen Genotyping, Fetal
Also known as: RHEGENO FE
Use
Fetal RhE/e genotyping is performed to assess the risk for alloimmune hemolytic disease of the fetus and newborn (HDFN). This genotyping evaluates the presence of Rh blood group antigens E and e, which are significant in predicting the antigen expression and potential for hemolytic disease from the maternal antibodies transferred to the fetus. Understanding the fetal RhEe genotype helps determine the risk for anti-e-mediated alloimmune hemolytic disease, which is characterized by red-cell hemolysis due to incompatibility between the maternal antibodies and fetal erythrocytes.
Special Instructions
Informed consent for genetic testing is required for New York patients. If the client is unable to culture, the 'Cytogenetics Grow and Send' test (ARUP test code 0040182) should be ordered in addition to this test, as ARUP will culture upon receipt for an additional fee. Backup cultures must be retained at the client's institution until testing is complete. Counseling and informed consent are recommended for genetic testing.
Limitations
The assay may not detect rare nucleotide changes leading to altered or partial antigen expression and null phenotypes. False-negative results can occur due to bloody amniotic fluid samples contaminating with maternal cells or RHCE-D-CE fusion genes. The test is limited in predicting genotype due to extreme variation in the Rh locus. Patients who have had hematopoietic stem cell transplants may yield inconclusive results. Additionally, abnormal signal intensities can result in indeterminate genotyping outcomes. The test was developed and its performance characteristics determined by ARUP Laboratories; it is not FDA-cleared or approved, though performed in a CLIA certified laboratory for clinical purposes.
New York Approved
Methodology
PCR-based
Biomarkers
LOINC Codes
- 59266-7
- 66746-9
- 31208-2
- 48030-1
Result Turnaround Time
3-10 days
Related Documents
For more information, please review the documents below
Specimen
Amniotic Fluid
Volume
10 mL
Minimum Volume
5 mL
Container
sterile container
Causes for Rejection
Frozen specimens in glass collection tubes.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 48 hours |
| Frozen | Unacceptable |