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24 Hour Urine Sodium Levels


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I just got diagnosed with POTS today after suspecting it for quite a while. My local hospital ran a 24 hour sodium urine test on behalf of the cardiology clinic and my GP told me the results were normal. The nurse at the clinictoday wanted to know what the actual numbers were. She said they should be over 150. When I got home I phoned the GP surgery and they told me my sodium was 54mmol.

I'm guessing this is too low. Can anyone here explain what it means please? I've already increased my salt and fluid intake and I'm due back at the clinic in 3 months time.



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It's nice to hear you've finally gotten a diagnosis. Hopefully your dr will figure out a treatment plan that will help you get better.

I had the same conversation about the sodium with my dr not too long ago.

The lab report states my numbers are normal (somewhere in the 70's), yet my dr is unhappy about the sodium saying that for a POTS patient it should be over 170. I'm drinking lots of fluids but I admit slacking off on the salt as it irritates my stomach.

I remember reading an article about the 24 h sodium in POTS patients having to be higher than the average people's but I don't recall the reasoning behind that. I'll look for it and if I can find it I'll share the link.



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This is in general, not POTS/dysautonomia specific...

24 hour urine sodium should be between 100-260 mEq/24 hrs (100-260 mmol/24 hrs)

It is hard to interpret the urine sodium without any information about the serum sodium...high serum (blood) sodium and low urine sodium is a very different problem than low serum and urine sodium. I have a good chart around here somewhere...

Alex - I can't handle as much table salt as I need, so I use mostly baking soda...all the sodium, none of the chloride (which I think is what bothers me).

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Thanks for the replies.

I didn't have any other sodium tests done, just the 24 hour urine collection. I found some websites that state normal values are between 40 and 220 mmol, which is probably why my GP said my result of 54mmol was in normal range. The POTSUK website says the goal is a volume of 1,500–2,500 ml and sodium excretion of 170 mmol/24 hours

I was wondering what my low result indicated and what I should be doing about it? I was already eating more salt when I did the test. I estimated I drank 2,800 ml and I passed 2,500 ml urine.



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Hypothetically, if you aren't excreting sodium because you are retaining it, then in POTS that's usually a good thing because it helps increase your plasma (blood) volume. However if you aren't excreting sodium AND your serum sodium is low then that could be caused by several things, including losing sodium through your GI tract (diarrhea).

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