Genomics Testing Laboratory

Bleeding Disorders Laboratory

The Genetics Testing laboratory for Bleeding Disorders evaluates patients with known or suspected Hemophilia A, Hemophilia B and Von Willebrand disease. The laboratory features considerable technical expertise in this specialized testing.

Highlights of our genetic test offerings:

• Von Willebrand disease – type 2
  • VWD 2A/2B/2M exon 28, with additional exons if initial screen negative
  • VWD 2 N exons 17-25
• Evaluations for hemophila A and B (F8 and F9)
  • DNA and cultured amniocytes
• Reference laboratory service for clinical studies and trials, including development of novel assays and use of research-based assays.
• Phone consultation to discuss laboratory results or approach to testing is available.  Dr. Barbara Konkle, the laboratory director, has over 25 years experience in interpretation of coagulation testing and application to clinical decision making.
• The laboratory works closely with the Washington Center for Bleeding Disorders at Bloodworks, directed by Dr. Rebecca Kruse-Jarres.  Patient referrals can be scheduled through 206-689-6507.
• Reference laboratory services for clinical studies contact:
  • Gayle Teramura, Laboratory Manager
• My Life Our Future (MLOF) project- (TBD)

Test Descriptions

• DNA Factor VIII Inversion
• DNA Hemophilia A Mutation Evaluation
• DNA Hemophilia B Mutation Evaluation
• Genotype for known Hemophilia/VWD mutation
• DNA Von Willebrand Disease Type 2A/2B/2M
• DNA Von Willebrand Disease Type 2N

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.

• Post Transfusion Purpura Workup
• Neonatal Alloimmune Thrombocytopenia Evaluation (NATP)
• Platelet Typing for Single Platelet Antigen

• HLA Class I (A,B,C) Typing
• HLA Class II (DR, DQ) Typing
• HLA-A2 or A*0201 Typing
• HLA-A29 Typing (Birdshot Retinopathy association)
• HLA-B*1502 Typing (Carbamazepine hypersensitivity)
• HLA-B27 Typing (Ankylosing Spondylitis, other arthropathies)
• HLA-B51 Typing (Behcet’s Disease association)
• HLA-B*5701 Typing (Abacavir hypersensitivity)
• HLA-B*5801 Typing (Allopurinol hypersensitivity)
• HLA-DQB1/DQA1 Typing (Celiac association)
• HLA-DQB1*0602 Typing (Narcolepsy association)