Serum electrolyte and acid base composition. The influence of graded degrees of chronic renal failure.

Data from 41 ambulatory patients with graded degrees of uncomplicated, chronic renal failure were used to define the quantitative relationship between serum acid-base and electrolyte composition and the serum creatinine level. Even in patients with only moderate renal insufficiency, serum total carbon dioxide (tCO2) content was reduced significantly. This early fall in tCO2 was offset by an increase in serum chloride (Cl-), serum undetermined anton concentration (A-) remaining normal. In patients with more severe degrees of renal insufficiency, further decrements in tCO2 occurred that were proportional to the increment in serum creatinine. These latter decrements in tCO2 were associated with equivalent increments in A-, serum Cl- remaining unchanged at the elevated level observed during moderate renal insufficiency. Confidence limits of 95% for tCO2 and A- were calculated from the data.