What is the normal FEV1/FVC ratio?

What is the normal FEV1/FVC ratio?

• A. 0.95
• B. 0.80
• C. 0.60
• D. 0.50

Answer: (B)

The key idea is that the FEV1/FVC ratio shows how much of the total forced vital capacity is expelled in the first second of a blow. In healthy adults, FEV1 is typically about eighty percent of the FVC, so the ratio is around four-fifths. This normal value matters because it helps distinguish patterns: in obstructive conditions, FEV1 drops more than FVC, lowering the ratio below normal; in restrictive conditions, both volumes drop but often in proportion, keeping the ratio near normal or even higher. Among the given options, a value around eighty percent best matches the typical, normal ratio. A value near ninety-five percent is unusually high and not expected in normal physiology, while values like sixty percent or fifty percent indicate an abnormal, reduced ratio consistent with obstruction or other airflow limitation, not a normal result. So, the normal FEV1/FVC ratio is about eighty percent of the FVC.

The key idea is that the FEV1/FVC ratio shows how much of the total forced vital capacity is expelled in the first second of a blow. In healthy adults, FEV1 is typically about eighty percent of the FVC, so the ratio is around four-fifths. This normal value matters because it helps distinguish patterns: in obstructive conditions, FEV1 drops more than FVC, lowering the ratio below normal; in restrictive conditions, both volumes drop but often in proportion, keeping the ratio near normal or even higher.

Among the given options, a value around eighty percent best matches the typical, normal ratio. A value near ninety-five percent is unusually high and not expected in normal physiology, while values like sixty percent or fifty percent indicate an abnormal, reduced ratio consistent with obstruction or other airflow limitation, not a normal result.

So, the normal FEV1/FVC ratio is about eighty percent of the FVC.