How is Obesity Hypoventilation Syndrome (OHS) diagnosed and what tests are required?

To diagnose Obesity Hypoventilation Syndrome (OHS), doctors look for signs of low oxygen and high carbon dioxide in the blood. This is often done using a blood gas analysis, which measures the levels of oxygen and carbon dioxide.

Additionally, a sleep study might be required to see how breathing changes during sleep. This helps in understanding if the person stops breathing or has shallow breathing when asleep.

Key steps in diagnosing OHS include:

1. Blood Gas Analysis: Checks for high carbon dioxide and low oxygen levels.
2. Sleep Study (Polysomnography): Observes breathing patterns during sleep.
3. Body Mass Index (BMI): Used to confirm obesity.

These tests help doctors understand if someone has OHS and how it affects their breathing, especially during sleep.