ABG Interpretation steps: How do you interpret ABG results and determine whether you have metabolic acidosis, metabolic alkalosis, respiratory acidosis, or respiratory alkalosis. The three things you need to know are the blood pH, the bicarbonate level, and the PaCO2. Once you know these values, you can determine what type of acid-base imbalance you have. A simple way of solving ABGs is to use a method such as the ROME or TIC-TAC-TOE method. Here's how to solve ABGs using the TIC-TAC-TOE