Ferriprox after Transfusion

Dear Thalpeople,
I just wondered if someone does have an explanation about a very rare and Interessting phenomenon.
  While I was using Ferriprox, the whole 11years (from 1994 - 2005) I had this symptom that the first day after my transfusion I did have absolutely no Urin colour. After the second day it starts turning red again. Since 3 months I turned back to Ferriprox, first coloured urin thru whole time and now since the last 2 transfusions, (I get mine every two weeks) it showed up again!! 
No Red colour for lets say about the first 30 hours or so.
I remember back in 95 - 96 I asked a Doc who was very familiar with L1 and he told me that this is a very rare symptom. I think it has no influence on the chelation because Iron still drops.
For example : July 2014 starting Ferriprox - Ferritin 2900, now  3-4moths later it´s around 2100
Does anyone have any Idea?? Andy?

Could it be that the urine is just diluted from the fluid given during transfusion, so it's not showing its normal color?

No I dont think so. The NaCl that I get during Transfusion is only 50ml. And Even if it were more could it Last for over 30 hours? There must be an other reason...
I think somthing like no free Iron. For a while.  Is that possible??

I found the answer. Right after your transfusion, your Hb is as high as it gets and it does greatly reduce bone marrow activity and erythropoiesis, resulting in less immediate demand for iron by the bone marrow. Patients see a reduction in iron excretion through urine when the Hb is higher, but a study of desferal showed that this was balanced by an increase in fecal iron excretion. Very little fluctuation in iron excretion was noted throughout the cycle. Basically, even though you don't see the iron being removed, it just switched how it's being removed after you get blood. It isn't the chelator not working, it's how and where the iron is being removed.
http://books.google.com/books?id=dMAG7N1fcU0C&pg=PA66&lpg=PA66&dq=is+iron+excretion+reduced+after+transfusion&source=bl&ots=DUjUUzaTvT&sig=RVNmhwFBt6V6GVXDJ6lqAVTIeRw&hl=en&sa=X&ei=GWY8VJ-mNc78yQTWt4GYAg&ved=0CEsQ6AEwBQ#v=onepage&q=is%20iron%20excretion%20reduced%20after%20transfusion&f=false

Yeah that seems reasonably although ferriprox is eliminating through the kidney. Tanks a Lot Andy.
You always got the answers! I like you man you are My Favorite Wise Guy ! 
We should call you consigliere...