Need bloodwork advisement

Kerry Isherwood

Hello!  I've just discovered this group and I'm bucking etiquette by posting before completing my horse's Case History but I have a time-sensitive inquiry:

I have a confirmed IR mare, 20yo drafty-cross, well-controlled with diet (Timothy Balance cubes) & maintenance Rx levothyroxine (Thyro-L).  Recently we started giving hyaluronate sodium (Legend) IV every month (we compete in rated eventing) and decided to move up our insulin testing to monthly to coincide with the injection/venipuncture (previously we were testing as needed, roughly every 3 months).  I drew blood this morning (Im a licensed vet tech) and sent it to Antech, our hospital's lab.  I'm doing the usual insulin:glucose plus a CBC/Chem (annual wellness check), and will add on a T4/ T3/ free T4 after my quick look through the groups links.  My question is, what blood tests could I add on with this draw to start screening for Cushings?  My equine vet & I hadn't given Cushings much thought b/c my mare is in such good body condition and her coat is not 'classically Cush' but the more research i do, the more I believe my mare is pre-Cushingoid---I'm just overwhelmed with the myriad of semi-useful blood testing (I do *not*T want to do the low dose dex test).  I only have a few days that I can add tests onto my already drawn blood sample, which brings this post full circle, and why I obnoxiously posted without all the pertinent facts of a proper case history:  I was just hoping someone would advise me post haste so I could start testing for Cushings with this blood draw instead of waiting another month (or worse, having to stick the old mare yet again!)

In summary:

Blood drawn 9/23/14, 8am
(2) serum separators and (1) lavendar EDTA tube

Antech tests requested:
equine insulin:glucose tests & ratio
T4 /T3 /free T4
.....what else should I add?  I know ACTH is not considered accurate due to the season but is it worth charting it monthly for the sake of trending?  Cost is not a major concern (for bloodwork, anyway, as I own my own hospital).

Lastly, my apologies if this post was not appropriate---if it is more appropriate to have a private consult with Dr. Kellon instead of clogging up the listserv then admin please kindly send me the proper channels for doing so! 

Thank you so much for enduring my lengthy post, and to all, I'm so so so excited to have found this group:  watching my mare struggle when her insulin spikes is emotionally devastating, and the trial and error I've had to navigate with diet has been difficult, to say the least.  I'm very much in need of a support group!  :)

~Kerry, LVT-VTS(ECC)
Licensed Veterinary Technician, Emergency & Critical Care Specialist
Brewster, NY;
"Pinky", 20yo QH/Draft mare, adopted 2004, former Premarin broodmare
diagnosed IR August, 2013
joined ECIR Sept, 2014

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