Sodium Analysis

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Sodium Analysis

paul spark
Hello.

May I ask what policies are in place for Sodium Analysis.

Here at Sheffield, we take two samples at commissioning and each PPM.
 1 A bicarbonate only sample
 2 A total sample with both acid and bicarb

We analyse sodium content with a IL 943 Flame Photometer.

The Flame photometer is no longer supported.

As there is no sodium calibration on the HD machine (Dialog+/Evo),
we are toying with the idea of relying on the conductivity calibration during commisioning/PPM and sending random samples off to the Labs for Sodium Analysis.

I dont recall ever recalibrating a machine because there was an incorrect reading from the Flame Photometer.

We have been offered an ionometer as a replacement - it doesn't seem very cost effective tho!



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Re: Sodium Analysis

Chris Bates
Hi Paul,
When we were getting a lot of high bicarb results from our labs I looked into trying a freezing point depression Osmometer. This seems to be a very accurate, quick and reproducible way of testing. The total osmolarity of the dialysis fluid is known as it is written on the acid can (291 mosm/l on ours). I don't know if anyone uses this technique but it always seemed like a very good method. They are around £3-4k and reference/cal solutions are not expensive. I couldn't get one to try but they analysed some of our samples and we got what I hoped.
Wolflabs and Camlab were the main suppliers of basic units as I recall. I considered splitting the costs with our QC dept but since then they have purchased an all singing new analyser.
I have heard of people having difficulties with ionometers but I believe Ian Morgan was happy with his Roche 9180 (?) electrolyte analyser.
Chris
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Re: Sodium Analysis

Ian Wilde
Administrator
In reply to this post by paul spark
Hi Paul,

We've never tested a sodium or bicarbonate in the 18 years I've been in renal.  My bosses never did it so in turn I have never done it (be this right or wrong).  I know that when we have a new machine commissioned there are no samples taken by the company either.
As with any sample, it's only accurate at the moment it is taken anyway!?  Can, worms, everywhere!
Ian Wilde
Renal Tech
Manchester University NHS Foundation Trust
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Re: Sodium Analysis

paul spark
thanks Chris.

I had an Instrumentation Labs Ilyte in for a trial.
It gave the results we wanted but the servicing costs seemed ridiculous!!.

Ian, I was considering doing away with sodium analysis - but, after looking at the post about bicarb conductivity and the table supplied by nikkiso, I think I would prefer to have some sort of sodium analysis available to me!!

Would be interesting to know how many other places rely solely on their conductivity meters!

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Re: Sodium Analysis

Ian Wilde
Administrator
If you're using a volumetric system and it is set up correctly and the calibration of your pumps checked then can it be wrong?
I know with the make of machine we use, if we got a bad result from the lab we would just check the volumes of the pumps was correct - and that would be pretty much all we could do anyway.
Ian Wilde
Renal Tech
Manchester University NHS Foundation Trust