Hi Reta,

Both of those upper numbers you are referencing are for normal horses.  For PPID horses we want to keep their ACTH level in the upper teens/low 20s (in pg/ml terms) year round.  8.9pmol/L translates to 40.4pg/ml as per Adrenocorticotropic hormone (ACTH) conversion to pmol/L, pg/mL, pg/dL, pg/100mL, pg%, pg/L, ng/L . Online converter from conventional units to SI units | UNITSLAB.COM which means Whistler is due for a dose increase.  Were he mine I'd look at bumping him up a full mg to try to get his level down.