The document discusses arterial blood gas (ABG) tests. ABGs are used to monitor acid-base imbalances by measuring oxygen, carbon dioxide, pH and bicarbonate levels in arterial blood. Kidneys and lungs work to maintain pH levels through compensatory mechanisms like regulating bicarbonate reabsorption or excretion. ABG tests are recommended for conditions affecting breathing or the kidneys. The procedure involves drawing arterial blood, usually from the radial or femoral artery, and analyzing it using an ABG machine with electrodes that measure levels of oxygen, carbon dioxide, pH and bicarbonate. Normal ranges for these values are provided along with interpretations of potential acid-base imbalances.