Each morning I load Claire and Daisy into the van and we drive 22 miles to the veterinary clinic on the south side of Missoula.
Once there, each dog has blood drawn and put in the appropriate tubes for delivery to the human hospital. Some of Claire’s blood also goes into a small container so that her blood can be analyzed on a different machine as well.
We drive north about two miles and drop off the small container to a veterinary clinic that uses an in-house testing method, the IDEXX Catalyst, to measure progesterone. The veterinarian who will be doing the TCIs prefers the IDEXX values but my veterinarian always uses the hospital lab — so we do both.
Another four or so miles and the two samples are delivered to the human hospital, where a masked attendant receives them at the door — very handy.
Who knew there were so many ways to measure progesterone?! They include chemiluminescence (CLIA), electrochemiluminescence (ECLIA), enzyme-linked fluorescent assay (ELFA), fluorescent enzyme immunoassay (FEIA), and two that are impractical in clinical settings but are considered “gold standards” — radioactive immunoassay (RIA), and liquid chromatography-mass spectometry (LC-MS).
The hospital lab has a machine (Siemens Atellica) that uses chemiluminescence to assess serum progesterone in blood. The IDEXX Catalyst uses some top secret proprietary technology that they would not reveal when I called Customer Service to inquire.
Yes, I have been nerding out over progesterone this week.
The IDEXX Catalyst does not appear to have been used in any peer-reviewed, published studies, although I did find one presentation that was peer-reviewed. Instead, there is considerable IDEXX-generated literature about their progesterone testing.
HMMMMMM.
That doesn’t mean their information is wrong! It just offers the critical thinker a reason to pause. When the company selling a product tells you how great and accurate it is — well, it might all be true but consider the source. And if it is so great — where are the peer-reviewed, published studies?
Like this one, which did not use an IDEXX machine, FYI:
Hollinshead, F. & Hanlon, D. (2019). Normal progesterone profiles during estrus in the bitch: A prospective analysis of 1420 estrous cycles. Theriogenology 125: 37e42.
Prospective study of 1400+ progesterone (P4) profiles in 1300 breeding dogs.
P4 measured using electrochemiluminescence (Roche Modular E170).
Relevant Findings:
LH0: P4 = 2.7 + 0.6 ng/ml and/or double its previous value.
Ovulation estimated between LH2 (P4 = 4.8 + 0.9 ng/ml) and LH3 (P4 = 7.2 + 1.3 ng/ml).
Fertile period is between 10 and 20 ng/ml (LH4 to LH7)
I did say I was nerding out, right?!
You can use the above to understand the table below, which is Claire’s progesterone results.
Interesting.