Thick dark blood while donating plasma
	
	
		Does anyone know what would cause your blood to be really thick and dark? I donated plasma for 4 months usually twice a week with no problem. Then in December twice they problems with my blood returning during the process.  They restuck me both times.  I didn't go back until Febrruary. I went twice in a week.  The next week they said my hematocrit was 35, too low to donate. I went back a week and half later my blood was really thick and dark and would not return.