What is up with pulse oximeters? Elizabeth Tracey reports

Do the devices known as pulse oxymeters, which measure the amount of oxygen in someone's

blood, underestimate or overestimate this value in people with darker skin?

Controversy swirls with release of data from an FDA-funded study that runs counter to

previous studies.

Rohan Mather, a critical care medicine expert at Johns Hopkins, frames the issue.

As a critical care doctor, taking care of sick people in the ICU, we have to measure

things that are crucial to making sure that someone's care is appropriate.

One of our critical devices is something called a pulse oxymeter.

It's what measures how much oxygenation we think you have in your blood.

Usually sits on your finger, and we've been using this for decades.

Just over the last few years, especially, there's been some controversy with these devices,

where we started to realize that these pulse oxymeters might not be as accurate as we think

they are, especially in people with darker skin.

Mather says it's clear additional research is needed.

At Johns Hopkins, I'm Elizabeth Tracey.