Dr. Connie Westhoff from the New York Blood Center joins Dr. Chaffin to discuss Rh genotyping in pregnant ladies and potential transfusion recipients with unexpected results on serologic D typing. Most laboratorians are aware that testing a patient for the D antigen can be challenging, especially when the results differ from previous results or if the reactions are “weaker than expected.” Dr. Westhoff helps us navigate this challenging area with an awesome summary of the basics of RhD testing, why and how the results can vary, a description of weak D and partial D, and finally, a potential management strategy for donors with unexpected results. If D testing has confused you, or if you don’t “get” weak or partial D, this is the episode for you!
Use the player above to listen to Episode 005 of the BBGuy Essentials Podcast!
DISCLAIMER: The opinions expressed on this episode are those of my guest and I alone, and do not reflect those of the organizations with which either of us is affiliated. Neither Dr. Westhoff nor I have any relevant financial disclosures.
The images below are generously provided by Dr. Westhoff.
- 1:52: Intro to Dr. Westhoff
- 3:38: Dr. Westhoff’s background
- 5:55: Dr. Westhoff outlines basic testing for RhD
- 9:38: “D” vs. “RhD” vs. “RHD“
- 10:46: Why is D testing different from that for K or Jka?
- 13:28: What’s an epitope?
- 16:42: Dr. Westhoff outlines “weak D vs. “partial D”
- 24:56: How practice differs between hospitals with D testing
- 28:00: Practice recommendation for pregnant females with weak D
- 32:57: Practice recommendation for weak D transfusion recipients
- 37:01: Proportion of serologic weak D that are types 1, 2, or 3
- 39:37: Cost and turnaround time breakdowns
- Sandler SG et al. It’s time to phase in RHD genotyping for patients with a serologic weak D phenotype. Transfusion 2015;55:680–689.
- Kacker S et al. Financial implications of RHD genotyping of pregnant women with a serologic weak D phenotype. Transfusion 2015;55;2095–2103.