Can whole blood from serum venipuncture be used for the dried blood spot test?
Again, this is a yes and no answer. For peptide hormone analysis (e.g., insulin, LH, FSH, etc.), results are the same for finger-stick capillary whole blood, venipuncture whole blood, and serum. If you are looking at endogenously produced steroid hormones (estradiol, progesterone, testosterone, DHEA-S, cortisol), the results are the same. However, if you have used one of these steroid hormones topically or sublingually, blood spot testing, showing capillary blood hormone levels, gives values much higher and more accurate than the venipuncture blood spot sample. This is because blood cells and serum that exit the capillary beds and return to the venous blood are “spent” of the bioavailable fraction of hormone. In this case, capillary blood more accurately represents tissue levels of the topically delivered hormone.
