Medical Laboratory Scientist ASCP Practice Exam 2025 – Complete Study Guide

Decreased values across all blood gas parameters, including pH, typically indicate metabolic acidosis. In this condition, there is an accumulation of acids in the body or a loss of bicarbonate that leads to a decrease in blood pH, reflecting an acidic environment. The key characteristic of metabolic acidosis is that it affects not only the pH but also the bicarbonate levels and often the partial pressure of carbon dioxide (pCO2) as the body attempts to compensate for the acidosis.

In metabolic acidosis, you would observe a low pH (indicating acidosis), a low bicarbonate level (which is a definitive marker of metabolic acidosis), and potentially a low pCO2 if respiratory compensation is occurring. This is different from other conditions where the blood gas parameters would vary differently, such as respiratory acidosis, which would primarily show increased pCO2 and possibly a normal pH depending on the compensation, or respiratory alkalosis, which typically reflects decreased pCO2. Metabolic alkalosis would instead show increased pH and bicarbonate levels.

Thus, understanding how the primary disturbance in metabolism leads to a decrease in pH and associated blood gas values is crucial in recognizing and diagnosing metabolic acidosis correctly.