SVC pulmonary function test

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Cherise77

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I was wondering what normal scores are on these tests?
In my Dad’s AMX0035 trial he’s been taking the test and they just gave him the numbers from the last 3 visits (visits roughly every 3 months now).
Numbers were 3.7 litres, 3.3 litres and today 3.03.
What do these numbers mean besides a decline?
Thank you for any knowledge you can provide us.
 
There is a calculation based on size, sex and age that gives a percentage of expected which is what I am always told after an svc not an absolute number. you could work it out as you know these numbers. Absolute numbers are less helpful than percentages
 
There is a calculation based on size, sex and age that gives a percentage of expected which is what I am always told after an svc not an absolute number. you could work it out as you know these numbers. Absolute numbers are less helpful than percentages
Thank you! Does anyone know what that calculation formula is?
 
Actually I found a calculator online. Says he should be around 3.6.
Does this mean we should now be talking to doctor about BiPap?
 
And in April this year when they said his reading was 76% what does that mean vs 3.03 litres?
sorry I’m so confused with these breathing tests
 
Im in that same clinical trial. :) They should convert that number into a % for you. You mentioned 76% in one of your comments, and that's a pretty good score.

You asked about BiPAP. For BiPAP most insurance will cover it when your FVC (NOT the same test) is below 50%. SVC is a bit easier of a test, I know for me personally my SVC is always higher than my FVC. Not sure if that's true of everyone but it's how it is for me.

You can always ask the neuro to convert the scores to % for you and share what those values are. The same for any of the data they take, you can speak up and ask them to tell you what it is and what it means. I know for me in the AMX0035 study, even though it's a research visit, if something comes up that concerns me regarding my health or support needs, I can ask about it and they will address it, even though that''s not what the visit is for. Or if they can't address it then and there, they will make a plan for a separate visit or phone call or whatever I need. I would imagine the neuro working with your husband is the same so don't hesitate to ask them anything.
 
My SVC is also always higher than my FVC. My neuro wrote an Rx for a trilogy after I had a sleep study. The study showed apnea. My FVC was high 70s when I got it.
 
The Medicare criteria for BiPAP in ALS are FVC<50% of predicted and/or MIP<60 cm. Check what the data is for his MIP as that criterion is often met several months ahead of the FVC.

Depending on which muscles are weak in what ways, SVC may be higher (more common) or lower than FVC. But the two are correlated and more clinics are using SVC as it's easier to perform more accurately in ALS.
 
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