ELI-PGY5

ELI-PGY5 t1_iu5i898 wrote

That’s gibberish. pH of blood changes in specific disease states. Checking blood pH is a common, useful pathology test.

As for 0.2 = “cells destroyed very quickly” “body would literally not function” - you’re exaggerating. A drop of 0.2 (7.4 to 7.2) would not even count as a severe acidosis.

So I rate your comment 3.2% the right answer, not 100%.

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ELI-PGY5 t1_iu5ei09 wrote

Sorry, it’s 2am and I misread. The guy I was responding to is too high not too low. Normal range for blood pH is .1 unit, I would disagree that pH varies by 0.2 in normal conditions, 7.2 to 7.4 is a pretty massive difference as you presumably know.

But that’s largely irrelevant to my point, which is that pH is not so stable that it can’t be used for diagnostic purposes. It’s just that it’s not used for the diagnostic purpose that the OP asked about, and the behaviour of tau proteins etc as noted in the reference doesn’t lead me to think that it is likely to be.

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ELI-PGY5 t1_iu56p3o wrote

  1. pH changes in bodily fluids are often clinically useful
  2. I don't really care about pH in CSF.
  3. I doubt it's a good test for Alzheimers, as we would presumably all be doing it if a $20 investigation could detect the condition. The linked article isn't very relevant to everyday clinical medicine.
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ELI-PGY5 t1_iu4v6gs wrote

The normal range for pH is 5 times that. And we see sick or sick-ish people outside that range pretty regularly. Pretty much everyone at my local hospital who gets blood drawn gets their pH checked.

But as to OPs question - my answer is no. We don’t have any simple tests for Alzheimer’s. MRI and PET provide decent info. But if pH on an LP was different, we’d suddenly have a simple, cheap-ish test for the condition.

pH isn’t a useful test on CSF in normal circumstances btw. We do care about pH in other fluids - pleural fluid, vaginal samples, blood etc.

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