Damage to blood samples and potassium readings

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lenistar

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Hi everyone,

Me again with another question ;)

Moritz had a blood test last week and his potassium measured quite high (6.6 mmol/l, normal range 3.4 - 5.0). I was very nervous and called the vet, who told me that due to damage to the blood sample (I believe she said during transport -- I'm living in Germany so may not have understood 100%), the potassium reading can be false. Because of this, they measure potassium directly at the vet's office, too. This reading was normal (4.38, normal range 3.0 - 4.8). I was calmed down, but now I'm staring to get nervous again and wanted to double check with you folks. There seems to have been some disagreement recently in the forum regarding damage to specimens and false potassium readings (I'm not sure if it's possible to quote from another topic in a new topic, so I'm just including the links):

viewtopic.php?f=28&t=61156&p=663495&hilit=hemolysis#p663495
scroll down to Lisa and Merlyn's entry which begins "Thanks myboo99" and continue reading. I'm mainly wondering about this post:

"Hi Lisa

This is true, potassium isn't usually elevated in cats with hemolysis and/or platelet aggregation. It's possible, and I know it's a big thing in humans, but in cats and dogs it's just not seen very often. And it doesn't affect sodium.

Let us know what happens with the blood test." (please note, I don't mean to criticize the person who wrote this. I'm just wondering if that info. is accurate.)

and here:

viewtopic.php?f=9&t=62641&p=678497&hilit=potassium#p678497
scroll down to Melissa and Bailey's entry beginning with "Hemolysis means" and continue reading.

and here:

viewtopic.php?f=28&t=62650&p=678194&hilit=potassium#p678194

I assume hemolysis is the name for the damage that can occur to a blood sample (I did some research online, but all of the medical jargon is quite confusing to me).

So my questions are: does damage to blood samples occur causing potassium readings to be higher than they actually are? And if so, can this be caused either by transport or error by the person drawing the blood? Can damage to the sample/error while taking the sample cause a potassium reading to be lower than it actually is? Since the reading taken at the vet's was in the normal range, there's no need to worry, right?

Thank you so much to everyone! I'm feeling rather overwhelmed at the moment (as you can probably tell by my post). I've been monitoring Moritz's diabetes super closely this past month, and I don't want to jinx it, but I feel like we're so close to not needing insulin anymore (he's just getting a touch now :smile: and he's been so brave and patient with all of the blood sugar measuring :smile: I'm sure you all know that close monitoring and lack of sleep can be exhausting, and sometimes you just get so nervous and overwhelmed.

Anyway, thanks again!
Elena
 
Scooters blood test was hemolyzed too and he did have an elevated potassium reading (6.6 as well) but his sodium was in normal range (153). I was told it does effect potassium but I don't know about sodium.
 
lenistar said:
This is true, potassium isn't usually elevated in cats with hemolysis and/or platelet aggregation. It's possible, and I know it's a big thing in humans, but in cats and dogs it's just not seen very often. And it doesn't affect sodium.


Elena


Absolutely wrong. Hemolysis (lysing or breaking of the red cells) will cause an increase in serum potassium levels---in dogs, cats, humans, etc. When the cells lyse, they release the intracellular potassium into the serum. That's just basic chemistry. It has nothing to do with the species that the sample came from. (and I have no clue why platelets were even mentioned there. )

9 times out of 10, hemolysis is due to the way the sample was drawn.
 
Is it possible that even though the damage to the sample was caused by how the blood was drawn, that the actual damage didn't occur until the sample was in transport? And that that's why the reading taken in the vet's office was within the normal range? I guess I just want to be sure that I can rely upon the reading taken in the vet's office (and thus rest assured that his potassium level is normal).

Thank you again!
Elena
 
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