The last two digits of the pH in metabolic acidosis will approximate the predicted PCO 2 . A lower value suggests concomitant respiratory alkalosis, a higher value suggests a concomitant respiratory acidosis. A detailed history and physical examination, together with appropriate further tests, usually help to narrow the possibilities considerably. In general, increased anion gap acidoses are more common, more likely to be seen in an emergency setting and more likely to be life threatening. Wide anion gap metabolic acidoses are disorders in which acidemia is caused by increased endogenous production of organic acids, as in lactic acidosis or diabetic ketoacidosis.
Renal insufficiency leads to impaired acid excretion.
History of established renal failure is usually present. Diabetic ketoacidosis - diagnosis depends heavily on history of diabetic mellitus, physical signs, and presence of hyperglycemia. Typical clinical picture includes poorly controlled diabetes or illness superimposed on diabetes. Since standard nitroprusside tests measure only AcAc, ketosis may paradoxically appear to worsen as patients improve, due to conversion of BOHB to measurable AcAc over time. Since the patient may have stopped oral intake days before presentation odor of alcohol on the breath is usually absent and the ethanol level may be zero.