Compass is still being developed and is effectively in beta. Some content and features may be incomplete, change, or not work as expected.

Content is anchored to trusted sources where available, but Compass has not yet been clinically reviewed. It provides general information rather than medical advice.

Feedback helps us identify gaps, errors, usability problems and opportunities to improve Compass over time.

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Tests and measurements

SVC

Slow vital capacity

The same idea as FVC, but breathing out gently rather than forcing it.

What it means

Blowing out steadily instead of hard. Some people can manage a more representative reading this way, particularly where a forced effort is tiring or where lip closure is difficult, so teams may record one or both.

Why you might hear it

  • Your results sheet may show SVC where you expected FVC.
  • Trials sometimes specify one rather than the other.

People who may help

Where Compass goes into this

About this explanation

These are plain explanations of words you may come across, not advice about your own situation. Where a word matters to a decision, the question pages go into it properly, and your own team is the place to take it.