Spirometry (lung function testing) results

While the poor attendee is blowing until they are purple in the face, we get to sit and look at all kinds of pretty graphs of how their lungs are performing, all of which are then condensed into this type of results table:

Spirometry results summary table - click for larger version Summary of spirometry results - click for larger or clearer version

That all looks very technical but the data on lung health from this is very straight forward and is essentially focused on two criteria:

How hard can they blow

This is the initial sudden burst of power as they exhale and it is used to tell us if there is a problem in the tubes leading to and from the lungs. For example, if there is a blockage in the tubes, the air is slowed as it has to pass through the narrow area, meaning they will get less air out in the initial blast and this will show up in the test. In the table above this is the FEV1 figure and ideally this will be over 80% in the second column from the left.

How long can they blow

This is the total volume of air they managed to exhale and tells us if there is a problem deeper in the lungs, in the lung tissue itself. For example, if something is affecting the lungs the total volume of air they can contain will be reduced and this part of the result will be lower telling us there is a problem deeper in the lung. In the table above this is the FVC figure and ideally this will again be over 80% in the second column from the left.

Predicted spirometry values

Spirometry   percentage  targets

So, this is the key bit - on the right hand side of the table at the bottom of the shaded bit are some percentages on the FEV1/FVC line, starting with 71% and going to 93%. This is the range of the expected result which is calculated from their BMI, age, gender, ethnicity, smoking history, etc. (Ethnicity does play a part here as some genetic groups do have a different lung capacity to others, for example people from south east Asia on average have a smaller lung capacity than caucasians).

In spirometry results table above, this person got a result of 80% against their expected range of 71% to 93%, with a target of 82%, therefore everything is hunky dorey and they are fine with no serious evident problems.

Further spirometry information

Wikipedia page on spirometry - includes info on all the spirometry acronymns, which are many and bewildering.

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