Using the normal A-a gradient estimate (age/4 + 4), what is the predicted gradient for a 60-year-old person?

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Multiple Choice

Using the normal A-a gradient estimate (age/4 + 4), what is the predicted gradient for a 60-year-old person?

This tests using the age-adjusted normal A-a gradient formula. The predicted alveolar-arterial gradient increases with age, commonly estimated as age/4 plus 4 (in mmHg). For a 60-year-old, 60 divided by 4 is 15, and 15 plus 4 equals 19. So the predicted A-a gradient is about 19 mmHg. This aligns with the understanding that a gradient near this value is normal for that age; a much higher gradient would suggest diffusion impairment or significant V/Q mismatch.

This tests using the age-adjusted normal A-a gradient formula. The predicted alveolar-arterial gradient increases with age, commonly estimated as age/4 plus 4 (in mmHg). For a 60-year-old, 60 divided by 4 is 15, and 15 plus 4 equals 19. So the predicted A-a gradient is about 19 mmHg. This aligns with the understanding that a gradient near this value is normal for that age; a much higher gradient would suggest diffusion impairment or significant V/Q mismatch.

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