Assess risk for alloimmune hemolytic disease of the fetus and newborn (HDFN) or hemolytic transfusion reaction. May be ordered for parental or fetal genotyping.
Polymerase Chain Reaction/Fluorescence Monitoring
Fetal Genotyping: Amniotic fluid OR two T-25 flasks at 80 percent confluency of cultured amniocytes. If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787.
WITH Maternal Cell Contamination Specimen (see Note): Lavender (K2EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).
Parental Genotyping: Lavender (K2EDTA), Pink (K2EDTA)
Amniotic Fluid: Transport 10 mL unspun fluid. (Min: 5 mL)
Cultured Amniocytes: Fill flasks with culture media. Transport two T-25 flasks at 80 percent confluency of cultured amniocytes filled with culture media. Backup cultures must be retained at the client's institution until testing is complete.
Maternal Cell Contamination Specimen: Transport 3 mL whole blood (Min: 1 mL)
Whole Blood (Parental Genotyping): Transport 3 mL whole blood. (Min: 1 mL)
Amniotic fluid: Room temperature.
Cultured Amniocytes: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to liability of cells.
Whole Blood or Maternal Cell Contamination Specimen: Refrigerated.
Plasma or serum. Specimens collected in sodium heparin tubes.
Patient History Form is available on the ARUP website or by contacting ARUP Client Services.
Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell Contamination Specimen: Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month
Background Information for RhC/c (RHCE) Antigen Genotyping
Characteristics: Erythrocyte alloimmunization may result in hemolytic transfusion reactions or hemolytic disease of the fetus and newborn (HDFN).
C Antigen Frequency: 0.68 Caucasians, 0.27 African Americans, 0.93 Asians.
c Antigen Frequency: 0.80 Caucasians, 0.98 African Americans, 0.47 Asians.
Cause: Antigen-antibody mediated red-cell hemolysis between donor/recipient or transferred maternal antibodies.
Polymorphisms Tested: Rh blood group RHCE*2 (C), RHCE*4 (c): c.307C>T; p.Pro103Ser and 109bp insertion.
Clinical Sensitivity: 99 percent.
Methodology: Immucor PreciseType™ HEA Molecular BeadChip which is FDA-approved for clinical testing.
Analytic Sensitivity and Specificity: 99 percent.
Limitations: Bloody amniotic fluid samples may give false-negative results because of maternal cell contamination. Rare nucleotide changes leading to altered or partial antigen expression may not be detected by this assay. Genotypes resulting in Rh null phenotypes will not be assessed. This assay is occasionally limited in predicting genotype due to extreme variation in the Rh locus. False-negative RhC or Rhc predictions may result due to RHCE-D-CE fusion genes. Patients who have had hematopoietic stem cell transplants may have inconclusive results on this test. Abnormal signal intensities may result in indeterminate genotyping results.
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.
Maternal specimen is recommended for proper test interpretation if contamination of the fetal specimen from the mother is suspected. Order Maternal Cell Contamination.
|Component Test Code*||Component Chart Name||LOINC|
|3002016||RHC GENO Specimen||31208-2|
- RHCE genotyping