The Different Types of D Variants

There are now greater than 500 RHD alleles that have been reported, and that number grows all the time. Those people we could call RHD positive, and then some others might have pieces like that one we just showed. There's also some non-functional RHD genes that are just turned off. But our biggest challenge is trying to differentiate the ones that we can consider the weak Ds,. And we can consider R HD positive, and others we should treat as being RHD negative.