Bioequivalence and Bioavailability Forum

Dear I. Shavan,

There are actually 2 points to consider:

• first point: the blood-to-plasma concentration ratio. If your analyte has a very high distribution into the red blood cells, hemolysis will artificially increase the plasma concentrations. See for instance as part of this paper from Gary Emmons and Malcolm Rowland on DBS: 0.5 % hemolysis is sufficient to increase plasma concentrations of tacrolimus by 10 %. This will be true whatever the bioanalytical method you're using. In such a case you need to be particularly cautious to avoid hemolysis during sample collection. Hemolysed samples will have to be flagged and their results may need to be rejected depending on the amount of hemolysis (define it clearly in the protocol). Whole blood may be a better matrix than plasma (whole blood is traditionally used for cyclosporine, for instance);
  
  
• the possible influence of hemolysis on your bioanalytical method. The EMA guideline on bioanalytical method validation asks you to test for differences in matrix effects, but problems with hemolysed samples can be due to other reasons. See for instance this paper from Nicola Hughes et al., or this one from Eugénie-Raphaëlle Bérubé et al.

The problem of hemolysed samples has been discussed at quite a number of workshops over the last few years. See for instance this white paper from the 2011 WRIB meeting. You will find many papers published in Bioanalysis and other journals.