Whereabouts in Australia are you located? If you are in the tropics/sub-tropics, you will have different reference ranges for the ACTH than those of us in more southern states.T he details of the ACTH test that Sherry mentions should be on the test result--if your vet hasn't emailed it to you, please ask them to do so. Sometimes there are comments from the lab on the test result that may indicate whether the sample was compromised at all. The ACTH level of 30 (I'm assuming the unit is pg/mL as all our labs use this) may have risen since March as we are in the seasonal rise.
Did you test insulin as well on 13 March?
Hang in there.
Maxine and Indy (PPID) and Dangles (PPID)
Canberra, Australia 2010