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Claire W asked...

I had a blood test to test for arthritis.

I had a blood test to test for arthritis. It came back negative but my GP said that the tests showed I had a raised level of sodium. He has requested a further blood test in a weeks time to see if its changed. What does this mean and what are the impacts?

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The answer

Low levels of sodium in the blood are relatively common. High levels are much less common, and if you’re feeling well otherwise it’s quite possible it was a ‘glitch’ in processing your sample, and the next reading may be normal.

The normal range for sodium is 135-145 millimoles/litre. Some people have naturally slightly high levels of sodium (say, 146-148 millimoles/litre) in their systems. Higher levels of sodium that don’t come down do need further investigation. They can be caused by dehydration, from diarrhoea and vomiting, diuretics (usually ‘water tablets’ given for high blood pressure) or kidney problems. A rare condition called diabetes insipidus, which affects the body’s ability to process water, is a much less likely cause.

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