Leptin


 

Just got faxed a friend's horse's blood test results.  I told her she needed to do ACTH, Insulin, Glucose and Leptin.  The ACTH came back at 241 pg/mL, but the Leptin came back at <1 ng/mL and Glucose was done at the vet's clinic and it came back as <10 mg/dL and their range is 60-125 mg/dL.  As far as I know no insulin was done so I asked her to ask the vet.  These tests were done at Cornell.  We know this horse is Cushings but he is a thoroughbred so could these low results be correct?

Jean and Amber
in VERY HOT South Carolina
August 2004


Kerry Isherwood
 

Hi,

I'm a licensed vet tech and let's just say, handle *lots* of blood, incl my own two IRs & one PPID.  I send to Cornell at least 2x/month.  I can offer a bit of insight:

....."Glucose was done at the vet's clinic and it came back as <10 mg/dL and their range is 60-125 mg/dL."....

>>> its likely the blood tube for the glucose test was not spun & separated in a correct timeframe for accurate results.  A horse with a true BG (blood glucose) of <10mg/dL would be....dead(!) or very close to it.  I've been conducting an informal study regarding glucose accuracy via veterinary glucometer at time of draw vs replicating BGs on same blood sample as a typical field veterinarian would be handling BGs sent to commercial labs (ie, blood is drawn into a serum separator tube, it sits in the vet's vehicle for at least drive back to clinic or for rest of day thru remaining appts, etc).  I've found **every single sample** so far to be lower on the samples sent to commercial labs.  One sample I did this week was on a friend's mini who we highly suspected of IR and her BG at draw on glucometer was 80mg/dL and on the exact same blood sample sent to lab that night was 40mg/dL (Antech lab, normals 60-125mg/dL).  That's a huge disparity!!  On this sample I purposely did not spin the blood right away to separate the cells from serum (again, replicating what would happen if a sample rides in a vet's car all day.  I knew results would be lower, but never guessed they would be **that much** lower.)  [note:  glucometer used is a veterinary model calibrated for equine blood]

I can only comment on the glucose results being not accurate and can only speculate that the samples were mishandled somehow.  Extrapolating from that, one has to wonder if the handling of the samples sent to Cornell were compromised, esp with a leptin below Cornell's normal of 1-4. 

Kerry in NY
Sept 2014


Eleanor Kellon, VMD
 




---In EquineCushings@..., <JKemmerer@...> wrote :

We know this horse is Cushings but he is a thoroughbred so could these low results be correct?
= = = = = = = = =

The glucose definitely is not correct. That level is incompatible with life.

Leptin is much more stable to the effects of sample handling:

Effects of sample handling on the stability of interleukin 6, tumour necrosis factor-alpha and leptin.

 

so it may be correct.  A lab's "normals" are only a reflection of the population they tested which may not have included many (if any) thoroughbreds.  That said, can't rule out an effect if the delay in processing or heat exposure etc. was more severe than in that study.


Eleanor in PA
www.drkellon.com
EC Co-owner
Feb 2001


 

Dr. Kellon and Kerry - So we know that the glucose is incorrect, I just saw Yoda walking around so he is alive ;-).  The ACTH is around the same results that she got about six months ago so I figure that is correct (he hasn't been on pergolide due to boarding problems) and if Leptin is very possibly correct I asked her to call the vet and see if they can call Cornell to do an insulin test on the sample that was sent to Cornell.  It will be interesting to see what the results of the insulin test are. 

Jean and Amber
in South Carolina
August 2004


Lavinia Fiscaletti
 

Hi Jean,

My previous post seems to have disappeared into a Neo black hole so apologies if this comes thru twice.

If this is the same vet and the samples were handled the same way, it could indicate that all the blood work has been compromised. That would mean the leptin level is actually higher, as is the ACTH. Same goes for 6 months ago. Either way, that ACTH is telling you the horse is extremely uncontrolled PPID and needs to be on meds. The risk for laminitis is extremely high and will only get worse as we begin to move into the seasonal rise period.

Given those parameters, I don't know that I'd waste money trying to add an additional test on a possibly compromised sample.

Lavinia, Dante, George Too and Peanut
Jan 05, RI
EC Support Team



Lavinia Fiscaletti
 

Hi Jean,

Kerry's right - that glucose can't be correct for a living horse (regardless of breed) so makes the rest of the results suspect for mishandling as well.

That ACTH is way too high and is likely even higher as it seems the sample may have been compromised - is the horse being treated for its PPID? If so, the dose of pergolide needs to be increased as that value is only going to rise as we enter the seasonal period.

Lavinia, Dante, George Too and Peanut
Jan 05, RI
EC Support Team



 

Lavina - I totally understand what you are saying but being Yoda is a thoroughbred the leptin just might be correct.  Yoda was tested previously (6 months ago) and started on 1.25 mg of pergolide from Thriving Pets.  Presently, he is boarded and was not given his medicine regularly.  They claimed he would not eat it.  Carol, the owner is 81 years old and couldn't go out to the barn regularly to make sure he got his pergolide.  So, in the end, everyone just gave up.  She just now has an opening in her barn, at her house, and we will be moving him home the end of the month.  She wanted him tested again and I suggested that she do it before she moves him so that he will be in a familiar place.  We are just trying to get all of our ducks in a row and prepare.  I am hoping that since the glucose was tested at the vet clinic that is where they mishandled that blood and maybe not the sample they sent to Cornell.  Just trying to determine if he is in anyway IR.  Being that he is a thoroughbred he probably is not but didn't want to take any chances.  Carol is insisting that we feed him Triple Crown Senior.  Her and I share our hay which I have tested and balanced so that is not a problem.  The glucose result was a red flag for me, but Yoda is very much alive.

By the way, we use different vets.  Thank goodness.

Jean and Amber
In South Carolina
August 2004