ABG Interpretation Exam with ans 2025
What is the normal pH range in an ABG? 7.35 - 7.45
What is the normal pCO2 range in an ABG? 35 - 45 mmHg
What is the normal HCO3 (bicarbonate) range in an ABG? 22 - 26 mEq/L
What is the normal PaO2 in an ABG? 80 - 100 mmHg
What does a high pCO2 indicate? Respiratory acidosis (pCO2 is an acid).
What does a low pCO2 indicate? Respiratory alkalosis.
What does a high HCO3 indicate? Metabolic alkalosis (HCO3 is a base).
What does a low HCO3 indicate? Metabolic acidosis.
What organ system regulates pCO2? The lungs (respiratory system).
What organ system regulates HCO3? The kidneys (renal system).
How fast can the lungs compensate in an acid-base imbalance? Within minutes.
How long do the kidneys take to compensate? Hours to days.
What is an uncompensated ABG? Abnormal pH and one abnormal value (either pCO2 or HCO3).
What is a partially compensated ABG? Abnormal pH with both pCO2 and HCO3 also abnormal.
What is a fully compensated ABG? Normal pH with both pCO2 and HCO3 abnormal.
What does ROME stand for in ABG interpretation? Respiratory Opposite, Metabolic Equal.
How do you identify a respiratory disorder using ROME? pH and pCO2 move in opposite directions.
How do you identify a metabolic disorder using ROME? pH and HCO3 move in the same direction.
Interpret: pH 7.56, pCO2 28, HCO3 25. Uncompensated respiratory alkalosis.
Interpret: pH 7.41, pCO2 56, HCO3 34. Compensated metabolic alkalosis.
Interpret: pH 7.16, pCO2 82, HCO3 29. Partially compensated respiratory acidosis.
Interpret: pH 7.36, pCO2 54, HCO3 36. Compensated respiratory acidosis.
Interpret: pH 7.50, pCO2 9, HCO3 7. Partially compensated respiratory alkalosis.
Interpret: pH 7.33, pCO2 30, HCO3 18. Partially compensated metabolic acidosis.
Interpret: pH 7.44, pCO2 50, HCO3 30. Compensated metabolic alkalosis.
If the pH is normal but on the lower end (e.g., 7.36) with high
Fully compensated respiratory acidosis.
pCO2, what is the likely diagnosis?
If the pH is normal but on the higher end (e.g., 7.44) with high
Fully compensated metabolic alkalosis.
HCO3, what is the likely diagnosis?
What is the first step in ABG interpretation? Check the pH to determine if the blood is acidic or alkalotic.
Check pCO2 and HCO3 to determine respiratory or metabolic
What is the second step in ABG interpretation?
origin.
Assess for compensation by checking if both pCO2 and HCO3 are
What is the third step in ABG interpretation? abnormal.
What value on the ABG tells you about oxygenation? PaO2.
What does low PaO2 suggest? Hypoxemia.
*COPD
What clinical condition is commonly associated with respiratory
*Hypoventilation
acidosis?
*Drug overdose
*Hyperventilation
What clinical condition is commonly associated with respiratory
*Anxiety
alkalosis?
*Early sepsis
*Diabetic ketoacidosis
What clinical condition is commonly associated with metabolic
*Renal failure
acidosis?
*Diarrhea
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What is the normal pH range in an ABG? 7.35 - 7.45
What is the normal pCO2 range in an ABG? 35 - 45 mmHg
What is the normal HCO3 (bicarbonate) range in an ABG? 22 - 26 mEq/L
What is the normal PaO2 in an ABG? 80 - 100 mmHg
What does a high pCO2 indicate? Respiratory acidosis (pCO2 is an acid).
What does a low pCO2 indicate? Respiratory alkalosis.
What does a high HCO3 indicate? Metabolic alkalosis (HCO3 is a base).
What does a low HCO3 indicate? Metabolic acidosis.
What organ system regulates pCO2? The lungs (respiratory system).
What organ system regulates HCO3? The kidneys (renal system).
How fast can the lungs compensate in an acid-base imbalance? Within minutes.
How long do the kidneys take to compensate? Hours to days.
What is an uncompensated ABG? Abnormal pH and one abnormal value (either pCO2 or HCO3).
What is a partially compensated ABG? Abnormal pH with both pCO2 and HCO3 also abnormal.
What is a fully compensated ABG? Normal pH with both pCO2 and HCO3 abnormal.
What does ROME stand for in ABG interpretation? Respiratory Opposite, Metabolic Equal.
How do you identify a respiratory disorder using ROME? pH and pCO2 move in opposite directions.
How do you identify a metabolic disorder using ROME? pH and HCO3 move in the same direction.
Interpret: pH 7.56, pCO2 28, HCO3 25. Uncompensated respiratory alkalosis.
Interpret: pH 7.41, pCO2 56, HCO3 34. Compensated metabolic alkalosis.
Interpret: pH 7.16, pCO2 82, HCO3 29. Partially compensated respiratory acidosis.
Interpret: pH 7.36, pCO2 54, HCO3 36. Compensated respiratory acidosis.
Interpret: pH 7.50, pCO2 9, HCO3 7. Partially compensated respiratory alkalosis.
Interpret: pH 7.33, pCO2 30, HCO3 18. Partially compensated metabolic acidosis.
Interpret: pH 7.44, pCO2 50, HCO3 30. Compensated metabolic alkalosis.
If the pH is normal but on the lower end (e.g., 7.36) with high
Fully compensated respiratory acidosis.
pCO2, what is the likely diagnosis?
If the pH is normal but on the higher end (e.g., 7.44) with high
Fully compensated metabolic alkalosis.
HCO3, what is the likely diagnosis?
What is the first step in ABG interpretation? Check the pH to determine if the blood is acidic or alkalotic.
Check pCO2 and HCO3 to determine respiratory or metabolic
What is the second step in ABG interpretation?
origin.
Assess for compensation by checking if both pCO2 and HCO3 are
What is the third step in ABG interpretation? abnormal.
What value on the ABG tells you about oxygenation? PaO2.
What does low PaO2 suggest? Hypoxemia.
*COPD
What clinical condition is commonly associated with respiratory
*Hypoventilation
acidosis?
*Drug overdose
*Hyperventilation
What clinical condition is commonly associated with respiratory
*Anxiety
alkalosis?
*Early sepsis
*Diabetic ketoacidosis
What clinical condition is commonly associated with metabolic
*Renal failure
acidosis?
*Diarrhea
1/2
