NTBI levels in C282Y homozygotes after therapeutic phlebotomy.

C282Y homozygotes exposed to sustained elevated transferrin saturation (TS) may develop worsening clinical symptoms. This might be related to the appearance of non-transferrin bound iron (NTBI) when TS≥50% and labile plasma iron (LPI) when TS levels reach 75-80%. In this study, NTBI levels were examined in 219 randomly selected untreated and treated C282Y homozygotes.

Monitoring phenylalanine concentrations in the follow-up of phenylketonuria patients: An inventory of pre-analytical and analytical variation.

Background: Reliable measurement of phenylalanine (Phe) is a prerequisite for adequate follow-up of phenylketonuria (PKU) patients. However, previous studies have raised concerns on the intercomparability of plasma and dried blood spot (DBS) Phe results. In this study, we made an inventory of differences in (pre-)analytical methodology used for Phe determination across Dutch laboratories, and compared DBS and plasma results.