How do you read a spirogram?

To read a spirogram, look at the flow-volume loop to assess lung function. The size and shape of the loop can indicate if there are any abnormalities such as obstructive or restrictive lung diseases. Key parameters to evaluate include forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and the FEV1/FVC ratio. Patterns such as a decreased FEV1/FVC ratio suggest obstruction, while reduced FVC may indicate restriction.