# How can I estimate blood pH?

Apr 10, 2014

The carbonic acid/bicarbonate buffer in Human blood regulates the pH to remain between 7.35 and 7.45 in order to prevent acidosis and alkalosis - and ultimately death due to extreme blood pH (Ellison et al. 1958).

$$What does that even mean?


Well, human blood should be, as stated above, between pH of 7.35 and 7.45. If it is below 7.35, then a person would have acidosis - in which their blood would be acidic and vice versa if it were over 7.45 - then the blood would be too basic.

A buffer is a system composed of a weak acid and its conjugate strong base OR a strong acid and its conjugate weak base. For example, if you had a buffer that is at a pH of 7.45 - that means if an acid is added to the mixture it would decrease in pH but then stabilize and go back to its original of 7.45. Same if a base was added then the pH would increase then stabilize back to 7.45. This is exactly how the human blood buffer works!

So to estimate the pH of blood of a healthy human being you can roughly say it is between 7.35 and 7.45!

Side note: If there is an increase in metabolism or $C {O}_{2}$ build up then the blood pH would become more acidic.