Genomics Testing Laboratory

Bloodworks Northwest performs molecular testing to identify genetic variants and polymorphisms.  We perform DNA-based tests for the fields of Red Cell Blood Groups, Hemostasis/Thrombosis, Hemophilia, Platelets, HLA, and Neutrophils. These molecular tests are powerful tools in the treatment and diagnosis of certain disorders.

The Genetics Testing Laboratory performs molecular testing for Bleeding Disorders and Red Cell Genomics.

Red Cell Genotyping

Molecular Genotyping for Red Cell Blood Group

Using molecular methods it is possible to identify genetic variations that control expression of red cell antigens on the cell surface. This can be done using patient, amniocyte or a blood donor DNA; intact red cells are not needed. Some examples of uses for genomic testing of red cell blood groups include:

• Patients that have been multiply transfused, or have pre-existing red cell antibodies that make serological red cell phenotyping not possible. In these situations, genotyping provides the red cell phenotype so that a transfusion service can provide partial or fully antigen matched red cells for transfusion.
• Certain patient populations require regular red cell transfusions and are at risk for making multiple red cell antibodies. Genetic testing of red cells can help to provide closer matches when selecting antigen matched cells for transfusion.
• Patients that have rare red cell phenotypes in which no commercially available anti-sera is available, such as Dombrock.
• Resolve discrepant serological testing results in blood donors and patients
  

Obstetrical Applications

In potential cases of hemolytic disease of the fetus and newborn (HDFN) blood group genomic testing can determine fetal blood group typing to help guide fetal monitoring during pregnancy.

Paternal zygosity of the father of the fetus is a modality that can predict the fetal red cell phenotype. Most red cell antigens including RhD are now available.

Test Descriptions

• RhD variant- weak D types 1,2,3 
• RhD Evaluation (weak or partial D eval)
• RhD zygosity 
• Red Cell Genotyping for Multiple Blood Groups  
• Red Cell Genotyping for a Single Blood Group (per Antigen System)
• ABO Genotyping
• Red Cell Genotyping for MNS system
• Red Cell Blood Group Sequencing
  • Requires prior authorization
  • Transaction Code: 3117-06

Limitations of Molecular Typing of Red Cells

• Red cell genetic identification does not always reflect the phenotypic expression of the red cell antigen, test results must be interpreted with knowledge of how these known polymorphisms affect blood group antigen expression on the red cell surface. For this reason, all red cell genomic testing results will be reviewed by laboratory staff prior to issuing a report.
• Molecular analysis periodically is performed by a microarray-based test. In rare cases where the individual has an antigen silenced by a frameshift mutation or deletion of the gene, which does not include the primer or SNP site, a positive phenotype will be reported.
• In cases of RhD zygosity testing, depending upon ethnicity, zygosity determination of the D gene may be inconclusive.
• The performance characteristics have been established by Bloodworks Northwest. The U.S. Food and Drug Administration (FDA) has not approved this test. However, FDA approval is not currently required for the use of this test. The results are not intended as the sole means for clinical diagnosis or patient management decisions.

Other DNA-based tests can be found at specific laboratory sites which are listed below.