In obstructive airway disease, an FEV1/FVC ratio less than 70% indicates which level of obstruction?

In obstructive airway disease, an FEV1/FVC ratio less than 70% indicates which level of obstruction?

• A. Mild obstruction
• B. Moderate obstruction
• C. Severe obstruction
• D. No obstruction

Answer: (A)

A reduced FEV1/FVC ratio (<70%) shows obstructive pattern because the amount you can blow out in the first second drops more than the overall forced expiratory effort, reflecting narrowed or blocked airways. Severity, however, is determined mainly by how much the FEV1 is reduced relative to its predicted value. If the ratio is below 70% but the FEV1 is still near normal (around 80% or more of the predicted value), this is categorized as mild obstruction. Moderate and severe obstructions correspond to progressively lower FEV1 % predicted (roughly 50–79% for moderate and 30–49% for severe). No obstruction would show a normal or near-normal FEV1/FVC ratio. With only the ratio provided, the typical interpretation is mild obstruction.

A reduced FEV1/FVC ratio (<70%) shows obstructive pattern because the amount you can blow out in the first second drops more than the overall forced expiratory effort, reflecting narrowed or blocked airways. Severity, however, is determined mainly by how much the FEV1 is reduced relative to its predicted value. If the ratio is below 70% but the FEV1 is still near normal (around 80% or more of the predicted value), this is categorized as mild obstruction. Moderate and severe obstructions correspond to progressively lower FEV1 % predicted (roughly 50–79% for moderate and 30–49% for severe). No obstruction would show a normal or near-normal FEV1/FVC ratio. With only the ratio provided, the typical interpretation is mild obstruction.