Anomalous electrolytes

RE: Anomalous electrolytes

Roland Bulkyn-Rackowe — Wed, 12 Sep 2018 18:59:20 GMT

Had a 5 month pup with addisons 2 years ago. Vomiting and inappetant, slightly low temperature. Potassium was 9.9 mmol/l, sodium 130 mmol/l, confirmed with ACTH stim test.

RE: Anomalous electrolytes

Julie Innes — Tue, 11 Sep 2018 10:13:37 GMT

[quote user="Iain Richards"]Learning Experience - re take sample if it's totally unexpected and incompatible with the clinical picture.[/quote]

Yes! I had a locum book me in a dog with suspected hyperparathyroidism based on a single (very) low calcium. I asked him if the dog had signs of hypocalcaemia and he looked a bit baffled. Apparently it had a little diarrhoea and was off its food, nothing else. Obviously repeat sampling showed calcium as normal. It was a good reminder to me to interpret all results in the context of the clinical picture!

RE: Anomalous electrolytes

Iain Richards — Mon, 10 Sep 2018 21:34:22 GMT

I didn't do the op and I don't think the nodes were biopsied. Dog is absolutely fine.

Thanks for the suggestions, I'm inclined towards an error from the sampling tube, I am as certain as I can be I filled hep first. Learning Experience - re take sample if it's totally unexpected and incompatible with the clinical picture.

RE: Anomalous electrolytes

Martin Atkinson — Mon, 10 Sep 2018 09:32:15 GMT

Did you biopsy the lymph node(s)?

Did you perform hematology at the same time? Don't want to teach granny to suck eggs but if the blood was put into an EDTA tube first even just touching the top of the tube with a the tip of the syringe can contaminate it enough to get an artifactually high K.

If this is a genuine hyperkalaemia and there was no diarrhoea/vomiting due to the GI issues then even though this dog is a bit young Addisons would be top of my differentials so ACTH stim test.

RE: Anomalous electrolytes

Phil Fox-Manning — Mon, 10 Sep 2018 07:37:59 GMT

I’m inclined to agree that EDTA contamination or lab error are most likely. If you have any of the sample left you could check total calcium, which should be almost zero if it’s EDTA contamination..?

RE: Anomalous electrolytes

Iain Richards — Sun, 09 Sep 2018 22:08:20 GMT

Sample taken from other leg. Like the thinking though!

RE: Anomalous electrolytes

Francisco Gomez — Sun, 09 Sep 2018 21:12:51 GMT

[quote user="Laurence Webb"]

[quote user="Francisco Gomez"]

Is the sample being taken from the IV cannula where the Hatmanns fluid is being administered?

[/quote]Interesting idea, but looking it up, Hartmann's only contains 4mmol/l of potassium.

[/quote]

True. Didn't think of that. Still looks like an error. Last time I had one of these I asked someone else to run the test (3rd time) and the result came up normal. The problems with repeatability is that we tend to repeat the mistake as well.

RE: Anomalous electrolytes

Laurence Webb — Sun, 09 Sep 2018 21:08:33 GMT

[quote user="Francisco Gomez"]

Is the sample being taken from the IV cannula where the Hatmanns fluid is being administered?

[/quote]Interesting idea, but looking it up, Hartmann's only contains 4mmol/l of potassium.

Were other electrolytes tests run over that period to check out machine error? As Beats said, it should probably be dead if the potassium is that high. I'd probably send some blood to an outside lab for comparison, if you've got any left.

RE: Anomalous electrolytes

Francisco Gomez — Sun, 09 Sep 2018 21:00:39 GMT

Is the sample being taken from the IV cannula where the Hatmanns fluid is being administered?

RE: Anomalous electrolytes

Beats — Sun, 09 Sep 2018 20:59:02 GMT

If the K+ was truly "off scale" then I think the pup would have been dead (assuming "off scale" means more than maybe 15mmol/L say). If it had just read an actual value of 9mmol/L or something I'd have recommended doing an ACTH stim test.

If you didn't take it, run it, etc yourself, then my money would still be on K-EDTA contamination or similar.