Table 3.

Correction factors (CFs) applied for the conversion of DBS to plasma concentration for each analyte and relative percentage of samples that meet the equivalence criteria (% equivalence).

Analyte	N of Samples	CF (CV%)	CF from Non-Volumetric DBS [24]	% Equivalence
letrozole	22	0.9 (5%)	0.9	100%
abemaciclib	20	1.0 (14%)	-	90%
M2	20	1.4 (18%)	-	75%
M20	20	0.8 (9%)	-	100%
palbociclib	3	1.3 (7%)	1.4	100%
ribociclib	5	1.2 (5%)	1.4	80%

% equivalence: percentage of ECpla with a %diff with Cpla within ±20%.