The CVh is best established over several lots (3 or more) and can either be the average
CV or more preferable, the highest acceptable CV over that period. CVs obtained during
times of instrument malfunction or significantly higher than the average CV should not
be used in calculations. If you have no previous CV data, then use the current CV as
the CVh basis and modify this value as you move on to subsequent new lots. This basis
value will need to be increased slightly (~1-2%) in order to establish QC ranges that are
not too narrow.