(Posting from a cell phone so I apologize about the lack of punctuation and potential misspellings ahead)
I am so Sorry to hear about your sisters struggles with her platelet count. When my husband, who was a version 16 also, had to get platelets almost every other day during induction and then at least twice a week during consolidation until his counts recovered. Sometimes I remember certain bags of platelets we were given gave a much bigger bump in numbers than other bags and we couldn't figure out the rhyme or reason to it and we didn't get many answers from the nurses or doctors either. I do remember when his reds got extremely low during round three of consolidation and his platelets were at 4 during an infection he would get a huge bag of red blood and a bag of platelets have remember the red blood not being his exact blood type but being a universal donor and he would not even get a bump in his counts from that huge bag I think it's just unique situations per persons body. I remember them running a test for something called hemolysis. I don't know if that involves platelets but I do know involves reds getting used up at a much faster rate than they should.
I remember thinking that his counts would never come back and was taking so long, but they always did on their own time I pray that's the case for your sister but as far as donating platelets and running the risk of potentially not be able to be a stem cell donor for her should she need one that's a very heavy decision and I'm sorry you have to contemplate that right now there's so much to worry about and focus on during this but she's at one of, if not the best, hospital in the nation for this disease and I would trust what the doctor say 100%
Prayers for your family.
Lea

Where I am treated, they maintain a list of the patience who require HLA matching for platelets. They save this when transfusions are rejected overtime. Many receive transfusions with a small bump. I usually git platelets every others day from day 12 to day 35. There wasno discussion regarding HLA typing until my last nadir because iI was not getting any benefit but eventually like every other time, they began to hold.

That is such great great that you are a bmt match. My one full sibling has never been tested and he is 58 with type two diabetes. I'm trusting God that I will never need that.

Just in case anyone else was wondering about this question, my sister asked her doctor at MDA and getting platelets from a sibling will only help if a person is already producing platelets on their own. If the body is not producing the platelets on it's own, it doesn't matter who donates, the numbers will plummet back down in a few days just like receiving platelets from a nonrelated donor.

My sister's had gone up from 5000 to 17,000 just prior to her bone marrow biopsy but they were back down on the morning of the bmb and they had to give her more platelets. All of her other blood work held their numbers so the doctor thinks she may be getting close to making it over the hump. Still waiting to see what the bmb showed. Won't know till the middle to end of the week.