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FEV 1 question
- Thread starter rnjessica
- Start date
I'm not sure I fully understand the question, but I'll try to answer it. Bear with me if I'm repeating stuff you already know. FEV1 stands for Forced Expiratory Volume in the first second of blowing out as hard as you can. In other words, the maximum amount of air you can blow out in 1 second. There is the *actual* amount of air you blow out, and there is the *predicted*.
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
I'm not sure I fully understand the question, but I'll try to answer it. Bear with me if I'm repeating stuff you already know. FEV1 stands for Forced Expiratory Volume in the first second of blowing out as hard as you can. In other words, the maximum amount of air you can blow out in 1 second. There is the *actual* amount of air you blow out, and there is the *predicted*.
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
I'm not sure I fully understand the question, but I'll try to answer it. Bear with me if I'm repeating stuff you already know. FEV1 stands for Forced Expiratory Volume in the first second of blowing out as hard as you can. In other words, the maximum amount of air you can blow out in 1 second. There is the *actual* amount of air you blow out, and there is the *predicted*.
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
I'm not sure I fully understand the question, but I'll try to answer it. Bear with me if I'm repeating stuff you already know. FEV1 stands for Forced Expiratory Volume in the first second of blowing out as hard as you can. In other words, the maximum amount of air you can blow out in 1 second. There is the *actual* amount of air you blow out, and there is the *predicted*.
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
actual - the volume of air they measure you blowing out:
predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
Scenario:
actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
Your percent predicted would be 75%.
If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
I hope that helps. Lemme know if I confused you!
I'm not sure I fully understand the question, but I'll try to answer it. Bear with me if I'm repeating stuff you already know. FEV1 stands for Forced Expiratory Volume in the first second of blowing out as hard as you can. In other words, the maximum amount of air you can blow out in 1 second. There is the *actual* amount of air you blow out, and there is the *predicted*.
<br />
<br />actual - the volume of air they measure you blowing out:
<br />predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
<br />
<br />Scenario:
<br />
<br />actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
<br />predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
<br />
<br />Your percent predicted would be 75%.
<br />
<br />If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
<br />
<br />Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
<br />
<br />I hope that helps. Lemme know if I confused you!
<br />
<br />
<br />actual - the volume of air they measure you blowing out:
<br />predicted - is their best guess of what a healthy person your sex, height, weight and age would blow out.
<br />
<br />Scenario:
<br />
<br />actual - So you go in and do your huffing and puffing: you blow out 3.0 liters.
<br />predicted - They look up in the tables and find their best guess of what a healthy person (your age, sex, height and weight) would blow is 4.0 liters
<br />
<br />Your percent predicted would be 75%.
<br />
<br />If you're monitoring your own lung capacity and are fully grown, then actual FEV1 volume could be a reasonable metric to use in the short term. But even healthy folks lose lung function as they get older. The key is to measure CHANGE in lung function. If at visit 1 you're at 75% predicted and at visit 10 you're still at 75% predicted, this is great news. However, if at visit 1 you're at 125% predicted and at visit 10 you're at 100% predicted, this is bad news. So, in short, you want to look for change in your "% predicted". You are your own yardstick.
<br />
<br />Whether you go by change in absolute volume, or change in % predicted probably doesn't matter all that much provided you're fully grown. However, over a long period of time % predicted is a better value to use. Even healthy people see a decline in lung function as they age (30 and older). IF you're still growing, then definitely percent predicted is the better metric to use.
<br />
<br />I hope that helps. Lemme know if I confused you!
<br />
No no you didn't confuse me <img src="i/expressions/face-icon-small-smile.gif" border="0"> Thanks for the input really! Here's the deal...my "predicted" is usually in the 60's, but "actual" in the 70's. So of course I'd like to look at the "70's" category and think yay! So that's why I was asking. SO when people say what's your FEV 1..I don't know to say in the 60's or 70's. You know?
No no you didn't confuse me <img src="i/expressions/face-icon-small-smile.gif" border="0"> Thanks for the input really! Here's the deal...my "predicted" is usually in the 60's, but "actual" in the 70's. So of course I'd like to look at the "70's" category and think yay! So that's why I was asking. SO when people say what's your FEV 1..I don't know to say in the 60's or 70's. You know?
No no you didn't confuse me <img src="i/expressions/face-icon-small-smile.gif" border="0"> Thanks for the input really! Here's the deal...my "predicted" is usually in the 60's, but "actual" in the 70's. So of course I'd like to look at the "70's" category and think yay! So that's why I was asking. SO when people say what's your FEV 1..I don't know to say in the 60's or 70's. You know?
No no you didn't confuse me <img src="i/expressions/face-icon-small-smile.gif" border="0"> Thanks for the input really! Here's the deal...my "predicted" is usually in the 60's, but "actual" in the 70's. So of course I'd like to look at the "70's" category and think yay! So that's why I was asking. SO when people say what's your FEV 1..I don't know to say in the 60's or 70's. You know?
No no you didn't confuse me <img src="i/expressions/face-icon-small-smile.gif" border="0"> Thanks for the input really! Here's the deal...my "predicted" is usually in the 60's, but "actual" in the 70's. So of course I'd like to look at the "70's" category and think yay! So that's why I was asking. SO when people say what's your FEV 1..I don't know to say in the 60's or 70's. You know?
NYCLawGirl
New member
Your actual number should not be a percent but rather a hard amount (e.g., 3.0 liters). Think of it this way: the only way to get a percent is to have a baseline (denominator) to take the measurement, and the only baseline they can use is the average for a person your age, weight, and sex. In other words, you have to be 70% of SOMETHING. If I blow out 2.3 liters of air in one second, the only way to convert that into a percentile is to measure it against something else, and when people refer to their percent of FEV1 they are talking about that actual number as measured against a "healthy" person of their same weight and sex. So I guess I'm a little confused how you could have an "actual" number that is 70% - have you asked your doctor what exactly this is a percentage OF?
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
NYCLawGirl
New member
Your actual number should not be a percent but rather a hard amount (e.g., 3.0 liters). Think of it this way: the only way to get a percent is to have a baseline (denominator) to take the measurement, and the only baseline they can use is the average for a person your age, weight, and sex. In other words, you have to be 70% of SOMETHING. If I blow out 2.3 liters of air in one second, the only way to convert that into a percentile is to measure it against something else, and when people refer to their percent of FEV1 they are talking about that actual number as measured against a "healthy" person of their same weight and sex. So I guess I'm a little confused how you could have an "actual" number that is 70% - have you asked your doctor what exactly this is a percentage OF?
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
NYCLawGirl
New member
Your actual number should not be a percent but rather a hard amount (e.g., 3.0 liters). Think of it this way: the only way to get a percent is to have a baseline (denominator) to take the measurement, and the only baseline they can use is the average for a person your age, weight, and sex. In other words, you have to be 70% of SOMETHING. If I blow out 2.3 liters of air in one second, the only way to convert that into a percentile is to measure it against something else, and when people refer to their percent of FEV1 they are talking about that actual number as measured against a "healthy" person of their same weight and sex. So I guess I'm a little confused how you could have an "actual" number that is 70% - have you asked your doctor what exactly this is a percentage OF?
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
NYCLawGirl
New member
Your actual number should not be a percent but rather a hard amount (e.g., 3.0 liters). Think of it this way: the only way to get a percent is to have a baseline (denominator) to take the measurement, and the only baseline they can use is the average for a person your age, weight, and sex. In other words, you have to be 70% of SOMETHING. If I blow out 2.3 liters of air in one second, the only way to convert that into a percentile is to measure it against something else, and when people refer to their percent of FEV1 they are talking about that actual number as measured against a "healthy" person of their same weight and sex. So I guess I'm a little confused how you could have an "actual" number that is 70% - have you asked your doctor what exactly this is a percentage OF?
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
NYCLawGirl
New member
Your actual number should not be a percent but rather a hard amount (e.g., 3.0 liters). Think of it this way: the only way to get a percent is to have a baseline (denominator) to take the measurement, and the only baseline they can use is the average for a person your age, weight, and sex. In other words, you have to be 70% of SOMETHING. If I blow out 2.3 liters of air in one second, the only way to convert that into a percentile is to measure it against something else, and when people refer to their percent of FEV1 they are talking about that actual number as measured against a "healthy" person of their same weight and sex. So I guess I'm a little confused how you could have an "actual" number that is 70% - have you asked your doctor what exactly this is a percentage OF?
<br />
<br />Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
<br />
<br />One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
<br />
<br />It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.
<br />
<br />Sorry, I feel like that was horribly confusing, but I can't come up with a more eloquent way to ask the question right now. Lazy sunday <img src="i/expressions/face-icon-small-wink.gif" border="0">
<br />
<br />One final note to keep in mind: your percent FEV1 can actually vary from machine to machine and from CF center to CF center. I learned this when I went to college and started using both my old Denver center and the new center in Atlanta. I would blow the same hard numbers and have a different percent (off by a few points) b/c they were using a different predictor.
<br />
<br />It's possible your doctor includes an extra number in your PFTs that measures the actual percent of lung function you are using, but that would be a volume number and not an FEV1.