Cornell ACTH vs eACTH tests/codes ? Update - Results back
Results for anyone interested in post 7.
Are the ACTH tests always endogenous?
Looking at their website info asf:
Test Name: ACTH Endogenous
Name: ACTH and Insulin
Descr: Equine only
Name: Insulin baseline
In the past we have ordered code ACTHIN - but just realized "endogenous" is not mentioned for that test/code. For that matter "baseline" is not mentioned for the insulin. Are they really the same tests - or is better to order them separately - assuming one wants eACTH and insulin baseline?
Also, the test days for (e)ACTH are M-F. For insulin M,W,Th.
I don't know if samples are sent overnight or two-day. If frozen, does it really matter which days they arrive? I am unclear - seems I read that one of the tests the samples are tested day of arrival - probably the ACTH. Seems I also read somewhere that samples should arrive the afternoon before testing. Insulin?
I know I am splitting a few hairs here - just want to better understand so can schedule the vet accordlingly. TIA.
Last edited by grayarabs; Sep. 15, 2011 at 08:26 PM.
You may already realize this but it is best not to do an endogenous ACTH test from about August till Dec because of the natural rise. The results are not as accurate and sometimes a waste of money. Some vets don't realize this so talk it over with your vet. Suspected horses are usually tested in the spring and summer. It is best to overnight the sample but once the blood has been spun in the centrifuge the sample can stay frozen at the vets office until the best day to ship it.
Best to talk to your vet--they do this stuff all the time. "Baseline" means it's just one value, one snapshot in time--it's not pre- and post-glucose challenge, nor is it an insulin: glucose ratio.
If you're not giving your horse ACTH, it's all going to be endogenous.
Proud member of the "I'm In My 20's and Hope to Be a Good Rider Someday" clique
Former owner of the best Amish-carthorse-turned-eventer ever
Yes, am testing to see the levels during the seasonal rise.
My horse was tested last Spring and was a bit above normal range ie 42.3 (9-35). He is on CTB. Will see. (and pray).
I was planning on calling the vet office tomorrow to schedule the blood draws - especially in regards to the insulin. (and cortisol and glucose?). I need to review my notes - but IIRC blood should be pulled 2-4 hours after horse starts eating morning meal. Is that right?
In the 04 August 2011 Prascend webinar (see below), Andy Durham of Liphook Equine Hospital said that horses with PPID have a much greater autumnal increase in ACTH than normal horses, therefore this is the BEST time to test for PPID as the difference between horses with PPID and normal horses is magnified, as long as a seasonally adjusted reference range is used. Liphook tested ACTH from 156 normal horses every month for a year and plotted the upper limit reference interval. August, September and October had a mean upper limit of 47 pg/ml with September having the highest at over 50 pg/ml. The mean upper limit for the rest of the year was 29 pg/ml with January, March, July, November and December all having mean upper limits over 30 pg/ml. "
Tks Katy. I went back to that website and just found the graph values.
Interesting. I think I can say that my horse is not IR. But I need to read again the (possible) relationship between T3/T4 and insulin/IR.
The ACTH of 96 - I don't know. Obviously it is not good. I guess no way to speculate if the CTB is doing any good. I'll keep my horse on it for now. Curious what effect the "berries" will have on his hair growth for winter.
Of course laminitis is my biggest worry. I'm doing the best I can with diet and exercise. If anything my horse is a bit underweight.
To add: Regarding the graph of Liphook and the mean number/value for PPID horses - March shows a number of around 60 and mid Sept of around 180 ie an average increase of 120. I am assuming the horses tested were not on meds. My horse FWIW went from 44 to 96 - an increase of about 50.
So I wonder if the CTB did/is helping against the rise in ACTH? There are really too many factors involved to even guess - but again - I wonder.
I have read different opinions on the ACTH numbers in regards to risk of laminitis. It does not seem to follow that the higher the number the increased chance of laminitis. Some camps consider any number above normal puts a horse at risk. Dr. Thomas seems to have a differing opinion?
Last edited by grayarabs; Sep. 15, 2011 at 11:48 PM.
I suspected my horse had Cushings this summer and I started CTB powder in June. Had his ACTH tested in early August (just before seasonal rise, I think) and his results were 712!!!! The CTB drastically reduced his symptoms (lethargy, muscle loss, excessive drinking/peeing) but apparently did nothing to his ACTH levels. Unless, of course, they were even higher than that.
I started him on 1mg of Pergolide, per vet, but am having him retested at the end of Sept. to see if it reduced his levels at all. Obviously he'll need a much higher dose to lower it 700 pts. I belong to the IR/Cushings Yahoo group and they say to raise the dose until the symptoms go away. However, I don't really want the symptoms to return, especially the weight/muscle loss, with winter coming, which will happen if I stopped giving the CTB. My horse will probably be rete$ted frequently to check the effectiveness of the dose.
Are you going to use Pergolide? I try to do things 'natural' when it comes to taking care of my horse, but CTB doesn't seem to reduce the ACTH levels; high levels can lead to laminitis..... this scares the crap out of me. Pergolide is more expensive than CTB, but not unafforadable. Your horse's levels are within a reasonable range and can be reduced. My BO's horse tested 99 and he's on 1mg for now.
So don't think that the positive changes you'll see with CTB is affecting the ACTH levels. BTW, my horse's thyroid levels were slightly low too. My vet isn't concerned at this point and thinks they will be OK if/when we get the ACTH under control.
Yes, he is on the Pergolide and CTB. I don't want the symptoms to return while waiting for the Pergolide to work, so I'm keeping him on the herbs.
I'm curious to know if there is an average range in the reduction of ACTH per mg of Pergolide. Like, 1mg can reduce it 50-100 pts. on average. Hopefully our horses can be reduced on lower doses; as I understand, as they get older and the disease progresses, higher doses are needed. Hmm, I'll ask the Cushings group about the average range question.