There are four primary abnormalities of acid-base balance:
Metabolic acidosis
Metabolic alkalosis
Respiratory acidosis
Respiratory alkalosis
These can be differentiated on the basis of changes in pH, serum [HCO3-] and pCO2.
| pH | serum [HCO3] | pCO2 | |
| Metabolic acidosis | ↓ | ↓ | ↓ |
| Metabolic alkalosis | ↑ | ↑ | ↑ |
| Respiratory acidosis | ↓ | ↑ | ↑ |
| Respiratory alkalosis | ↑ | ↓ | ↓ |