Relative T/S ratio (n = 10) measured in WB collected by venipuncture in various anticoagulants and DBS samples (blotted with WB or directly from the fingertip) from a single individual.

aWilcoxon signed-rank test to compare between WB and WBDBS of the same anticoagulant
bFriedman’s test to compare anticoagulants within WB and within DBS
cDBS made from finger prick spotted directly onto paper (no anticoagulant)
Abbreviations: T/S  =  relative telomere length ratio, SD  =  standard deviation, CV  =  coefficient of variation, WB  =  whole blood, DBS  =  dried blood spot, ACD  =  acid citrate dextrose anticoagulated, EDTA  =  Ethylenediaminetetraacetic acid anticoagulated