<P> Acidosis is a process causing increased acidity in the blood and other body tissues (i.e., an increased hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma . </P> <P> The term acidemia describes the state of low blood pH, while acidosis is used to describe the processes leading to these states . Nevertheless, the terms are sometimes used interchangeably . The distinction may be relevant where a patient has factors causing both acidosis and alkalosis, wherein the relative severity of both determines whether the result is a high, low, or normal pH . </P> <P> Acidosis is said to occur when arterial pH falls below 7.35 (except in the fetus--see below), while its counterpart (alkalosis) occurs at a pH over 7.45 . Arterial blood gas analysis and other tests are required to separate the main causes . </P> <P> The rate of cellular metabolic activity affects and, at the same time, is affected by the pH of the body fluids . In mammals, the normal pH of arterial blood lies between 7.35 and 7.50 depending on the species (e.g., healthy human - arterial blood pH varies between 7.35 and 7.45). Blood pH values compatible with life in mammals are limited to a pH range between 6.8 and 7.8 . Changes in the pH of arterial blood (and therefore the extracellular fluid) outside this range result in irreversible cell damage . </P>

In case of acidosis the ph of the blood is