Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (618 page)

Normal or Increased Serum Potassium

   Hydronephrosis

   Early renal failure

   Administration of HCl (e.g., ammonium chloride)

   Hypoadrenalism (diffuse, zona glomerulosa, or hyporeninemia)

   Renal aldosterone resistance

   Sulfur toxicity

   Diagnostic Findings

   Serum pH is decreased (<7.3).

   Total plasma CO
₂
content is decreased; <15 mmol/L almost certainly rules out respiratory alkalosis.

   Serum potassium is frequently increased; it is decreased in RTA, diarrhea, or carbonic anhydrase inhibition; also, increased serum chloride.

   Azotemia suggests metabolic acidosis due to renal failure.

   Urine is strongly acid (pH 4.5–5.2) if renal function is normal.

   In evaluating acid–base disorders, calculate the AG (see earlier discussion).

LACTIC ACIDOSIS