Freestyle Libre consistent LO readings on underweight cat

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JamieH

Member Since 2019
Hi everyone,
Yesterday afternoon Cat has his first Freestyle Libre sensor installed and ever since the sensor has come online it has only read LO or, at most, listed his glucose at 43. I know there is some difference between interstitial glucose readings and blood glucose readings, but his actual blood glucose has been averaging 235 during this time, and I was expecting the readings to only potentially be off by 100 points at most.

Cat is very underweight, body score 2/9 and currently sitting at 6.1 pounds. Healthy weight for him was 9.5 pounds but he hasn't been able to get back to that in a few years due to intestinal cancer mostly.

I was wondering if anyone else had a very underweight cat who had the libre sensor and also experienced LO readings consistently?

Note that Cat can't take insulin if his blood sugar is below 300 - all we have is Lantus, and even 0.5 units is enough to send him into hypoglycemic shock if his BG is below 300. We learned that the hard way. So, for the last 3 days, since his BG has been lower he's not been getting any insulin.

Cat also has kidney disease but has not had any subq fluids since wearing the sensor, so that wouldn't be affecting the readings either.

The only other possibility I can think of is an installation error. Cat is the first patient my primary care vet has placed a sensor on. But the placement is nearly identical to that of my cat Muffy who had her sensor placed by my internal medicine vet, and she has been using these sensors for about as long as they've been available.
 
I have not used the Libre, I've only seen it installed on a friend's cat, but Wow, that is disconcerting.

When you say "his actual blood glucose has been averaging 235 during this time", I assume you mean with a regular meter via ear or paw prick. Is it a human meter or pet meter? Do you have any control solution for your regular meter, or have you tested yourself maybe first thing in the morning (assuming you aren't diabetic) with your regular meter? I'm just trying to figure out if the regular meter is wrong since it is easier to validate, because if the Libre is not the one that is wrong, then schnikey we have a problem. Is there even a way to calibrate the Libre, or "reboot" it?

I think I would be inclined to have your primary vet replace it, or confer with your IM.

If you are able to test the traditional way, why the Libre? Just curious, and sorry if you already answered this elsewhere.
 
Hi Sandi,
For testing blood glucose I use the AlphaTrak2 with AlphaTrak2 strips, and get blood from the ear. The meter and strips are reading properly when I test with control solution, so I know my meter is accurate. I also keep a human meter on hand (just for fun) and when I test both meters on myself they're comparable.

The Libre sensor is basically a mini computer that can test blood sugar. Apparently it ran some diagnostics against itself about an hour ago and decided that death by suicide was the appropriate action. So, the sensor is finished now. Once their internal computer shuts down they're dead forever, so I can't reset it at all. Libre's don't come with any external calibration capability. They go through a 1 hour calibration period when they're first installed and activated. After that they have a mind of their own.

I've got a visit with the IM vet on Friday morning with my other diabetic (Muffy), so I'll ask the IM vet if she's seen this before.

The regular vet who placed Cat's sensor is off until Monday. I'll leave an update for her with the sad news of the sensor's death when I'm in that clinic Friday evening with a different cat (Thomas).

The reason I did the Libre for Cat... mostly I was just willing and financially able to let my vet practice on Cat (and also secretly super lazy, so I like stuff to be easy). She's really wanted to be able to use the Libre with her patients, but it's hard to to find people who can afford to do it. And the ones who need it the most are generally newly diagnosed and they've got enough going on that volunteering for new/expensive testing when the vet hasn't done it before is a scary prospect. Cat is really easy to do anything with. He doesn't mind ear sticks, or injections, he doesn't seem to notice subq fluids, and he LOVES taking pills. Muffy, my other diabetic, is the opposite. She HATES ear sticks, and I'm not normally allowed to touch her feet. She very grudgingly tolerates injections and subq fluids, and only accepts pills when completely hidden inside Temptations treats.
 
Ugh. Sorry for the premature death of the Libre and the background for giving it a whirl.

Good luck with Muffy on Friday, and hopefully the IM vet can at least tell you if she's seen such a spectacular failure of the sensor before. Would be nice if you could get the manufacturer to replace the sensor since it sounds like it was freaky from the start.

Talking about Muffy - I am totally spoiled with Whispy too. He comes right to his testing rug when I call him, he purrs through the whole BG test and won't take his first bite of food until he feels me give his injection. But if our Molly had diabetes?!? Jiminy Crickets I don't know what I would do. Have a stroke two times a day trying to catch her just to give shots, I guess! :eek:

Let us know how it goes.
 
I have one of these for myself. The readings are typically off the first 12-24 hours. If not reading correctly by 24 hours or getting repeated errors, chances are it is not installed correctly.
 
Where was the sensor attached?
I have attached the first sensor to my Badger with the help of my vet. I attached two sensors to my foster Wiggles myself with the help of someone else sith it requires two people with one to hold the cat. All three sensors were attached in the neck area.
Does it appear that there is a enough subcutaneous skin depth such that the sensor filament in not in the muscle or tissue below the skin layers.
Here is my writeup on using the Libre. Near the end is the comparison of Libre compared with reading from my human meter. My meter read lower that the Libre at the beginning but then over time the Libre read lower.
 
Larry and Kitties said:
Where was the sensor attached?
Click to expand...

Hi Larry,
The sensor was attached at his shoulder. I have a photo and full update about his experience at https://felinedm.com/tips-tricks-an...itoring/freestyle-libre-sensors-in-my-cats/#c

No, there definitely wasn't enough subq skin depth to accommodate the sensor. It turns out that Cat doesn't have enough subq depth anywhere on his body to correctly install the sensors. A good (if pricey) learning experience. On the upside, I've left the sensor in place to see how long it will stay on and it's still there after about 5 days, which is better adhesion than I got with my other diabetic cat (Muffy). I'm leaving Cat's sensor on to see how long it takes to fall off, or loosen enough that I can get adhesive remover underneath it to get it off easily. Right now it's too firmly fixed in place.

Cat has developed a strong and "bitey" aversion to going to the vet, so he was completely sedated for his install process. At home he's calm enough that, if he weren't too skinny, I'd be able to install a sensor on him with no help.

Is there a link missing for your writeup on using the Libre? I'd love to read that, but I don't see a link.
 
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