PFTs Are a High-Skill Task in a Low-Transparency System

Pulmonary function testing is strange. From the outside, it looks simple. A patient breathes into a machine. Numbers come out. A report is generated.

But the result doesn’t just come from the machine. It depends on how the test is performed. Effort, timing, coaching, judgment—small differences can change the result, even when the test technically meets criteria.

That part isn’t obvious if you’re not the one doing the test. And the system doesn’t make it obvious.

A fast, sloppy test and a careful, well-executed one can both produce reports that look acceptable. The numbers are there. The criteria are met.

Sometimes there are clues. The waveforms. Comments. Sometimes those comments say: “Testing met ATS standards for acceptability and repeatability.” Often when the testing didn’t.

So the report ends up carrying more confidence than the process behind it.

Most of the time, that doesn’t matter. But sometimes it does.

And when it does, the difference between a solid test and a marginal one isn’t always clear from the result alone.

Pulmonary function testing depends on skill. The system doesn’t reliably show it. That’s the problem.