PTH assay - PRE and POST calcitriol

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Lisa dvm

Lisa dvm

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I am looking for data for PTH levels - pre and post calcitriol.

Choy-Fong.....I think that you ran pre and posts on Meowzi and got some significant changes. Can you summarize her data for me?

Anybody else?

Thanks!
 
Of course I can summarize it :)

PTH (0-4)
12/5/08: 17.2 H
12/20/09 : begin calcitriol @ 3.5 ng/kg/day
12/29/08: 4.8 H
2/3/09: 1.5
3/20/09: 0.8
3/28/09: decreased calcitriol dose to 2.5 ng/kg/day due to elevated iCa and P
4/21/09: 1.2
7/10/09: 1.4
11/17/09: 1.7
11/25/09: decreased calcitriol dose to 2.32 to 2.44 ng/kg/day b/c of slightly elevated iCa

Corresponding renal, P, Ca and iCa values for those dates can be found in her Labs spreadsheet; the link is in our signature.

Note: Calcitriol has always been dosed on the intermittent schedule i.e. every 3.5 days, never daily. Her dosage has fluctuated a little in recent months b/c of some weight fluctuation.

I sort of suspect, but nobody will confirm, that we saw such a rapid and dramatic decline in her PTH at the beginning because we had started at too high a dose (per Dr N's protocol, it was indeed the recommended dose for her creatinine value, but we had to reduce the dose quickly after 3 months). As her PTH maintained quite nicely through last Nov. on the reduced dose, I'm inclined to say the smaller dose wasn't inappropriate for her. Her next assay will be in mid-Feb; we hope she's still stable in that range.

So Dr P, I have a question. If the ref range is 0-4, is a PTH of 1.0 better than a PTH of 3.0, or do we care as long as it's within the ref range?
 
So Dr P, I have a question. If the ref range is 0-4, is a PTH of 1.0 better than a PTH of 3.0, or do we care as long as it's within the ref range?
Click to expand...

I am going to assume that all is well if we are in the normal range. Of course, Dr. Nagode is the expert in this area (along with Dr. Chew) so all of us non-research types just take our cues from them.

That said, *personally* I would be happier at the lower end of the ref range simple because we are not measuring it all that often and so.....if at the top of the range....I would worry more about that lack of 'cushion' between where they are (if, say 3.5) and what would be considered elevated.

Thanks so much for the summary. Few clients spend the big bucks to measure PTH even once...let alone as well as you are monitoring. You are a rarity! :-D
 
Lisa dvm said:
I am looking for data for PTH levels - pre and post calcitriol.

Choy-Fong.....I think that you ran pre and posts on Meowzi and got some significant changes. Can you summarize her data for me?

Anybody else?

Thanks!
Click to expand...

I am efforting to connect our Bloodwork and BG level SS as we speak.

Pre calcitriol: 5.8 (ref range 0-4pmol/L)) PTH/1.31 iCA (1.0-1.4mmol/L ref range)

Two months post calcitriol start.
3.3 PTH, 1.34 iCa

need any other info?
 
Hi Cyn,

I was pretty sure that you were also doing PTH assays on Cosmo.

Thanks for the data.

What dosage is he on? The range is usually 2.5 - 3.5 ng/kg/day.

Are you dosing daily or every 3.5 days?
 
Lisa dvm said:
Hi Cyn,

I was pretty sure that you were also doing PTH assays on Cosmo.

Thanks for the data.

What dosage is he on? The range is usually 2.5 - 3.5 ng/kg/day.

Are you dosing daily or every 3.5 days?
Click to expand...

Hi Dr Lisa,
We do the twice weekly (every 3.5 days). He's on the lowest recommended dose.... 2.5 ng/kg/day. However, I think when we started the Calcitriol, we started dosing every other day. Then after the second assay, we did the every 3.5 days.

The bloodwork should be on a separate tab on the SS now....
 
Hi Dr Lisa,

I heard back from one of our listmembers who has a cat on Calcitriol. We corresponded a few times about Zoe's treatments; Zoe's mom said I could forward that to you off-list, if it would be useful. Zoe's diagnoses and labs are posted here: http://libbyandzoe.webs.com/zoelabs.htm

CBC, chem27, T4, urinalysis and other labs are also posted; her PTH info is near the bottom of the page.

Zoe started taking Calcitriol a few days after her 10/29/07 labs. Her dose is 11 nanograms per day, which works out to approx 2.5ng per kg, although her weight has varied a bit. This dose has remained the same the whole time she has been taking it and she has been receiving it every day (no time off) since first starting.

All tests done at MSU except 3/13/09 which was done at Idexx

10/29/07 PTH 32.9 - pre-Calcitriol
6/10/08 PTH 23.8
2/13/09 PTH 22.8 Renagel added after this test to help bring down PTH level
3/13/09 PTH 22.4 (first test after adding Renagel)
6/15/09 PTH 16.30
1/4/10 PTH 22.40

Hope this is helpful.
Deb, angel Evie, and the boys
 
More data points :mrgreen: (3/2 and 3/10, in blue font)

PTH (0-4)
12/5/08: 17.2 H
12/20/09 : begin calcitriol @ 3.5 ng/kg/day
12/29/08: 4.8 H
2/3/09: 1.5
3/20/09: 0.8
3/28/09: decreased calcitriol dose to 2.5 ng/kg/day due to elevated iCa and P
4/21/09: 1.2
7/10/09: 1.4
11/17/09: 1.7
11/25/09: decreased calcitriol dose to 2.32 to 2.44 ng/kg/day b/c of slightly elevated iCa
3/2/10: 13.5 H
3/13/10: raised calcitriol dose to 2.73 ng/kg/day
3/30/10: 3.2
5/22/10: because of weight loss, dose is now 2.80 to 2.90 ng/kg/day

6/29/10: 0.5 (new assay: ref range 0.4-2.5)
7/10/10: decreased dose back down to 2.73 ng/kg/day, bumping against high limit for iCa


Re: March data: that drop back to normal range was after five administrations of the new dose. I had doubts the new dose would be enough: we only went up by around 0.40 ng/kg/day; that seems sooo little (even though was a 17% increase). Even Dr S said he didn't know if it would be enough, and we were prepared to raise it a little more today. But I was pleasantly surprised when I picked up the fax last night. (He will be too, when he gets back from vacation next week). It's pretty potent stuff, huh?

eta: 6/30/10 data
 
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