Looking Under the Hood of the Braun ThermoScan 7 Thermometer

The Braun ThermoScan 7 thermometer is the most recommended by pediatricians. But how exactly does it work?

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This story was produced in partnership with Braun.

A kid’s temperature can say a lot about how their body is reacting to hidden problems, be it an infection, emerging teeth, or an overactive immune system. That makes a good thermometer an essential tool for any pediatrician, parent, or caretaker and a device they should research before purchasing. So it’s telling that more pediatricians recommend Braun than any other brand, and it’s worth exploring what, exactly, makes Braun thermometers so popular.

What makes a thermometer accurate, fast, and easy-to-use? How do they work? We turned to Richard McDuffie, a mechanical engineer who’s worked on these thermometers for nearly 13 years, to discuss what exactly sets the latest Braun thermometer, the ThermoScan 7, apart from the competition.

The Speed

A fast thermometer is a good thermometer, particularly when you’re trying to measure the temperature of a squirmy kid. Old-school liquid-filled glass thermometers take between two and five minutes to take a reading while the mechanical sensors in a digital stick thermometers can take just as long. And the quicker stick thermometers simply aren’t all that reliable.

“Any digital stick thermometer that provides a reading under 60 seconds most likely uses a predictive algorithm to estimate what the peak temperature is likely to be if you waited longer than a minute or several minutes,” McDuffie explains. “There is potential for this mathematical estimate to differ high or low versus the real, actual temperature.”

Infrared technology like that in Braun thermometers can take an accurate reading in one to three seconds, as converting the volume of infrared light into a heat or temperature value is a simple calculation, a factual scientific relationship that software can calculcate and a computer chip can process in less than a second.

The Surface

Taking your kid’s temperature in their ear is much more pleasant (for both parties) than their rectum and more accurate than their mouth, where you have to keep the probe jammed under their tongue for a while. Using ear thermometers like the ThermoScan 7 gives parents “a clear definition of where it’s going to go, how it’s going to be used, and the the likelihood of a user error is less than putting it in the mouth,” McDuffie says.

So while it’s tempting to opt for a thermometer with flexibility in testing sites, the majority of parents will be happy taking their kid’s temperatures via the ear canal, an easy to find target that leaves little room for operator error.

The Tech

McDuffie is as effusive when talking about the tech that’s packed into this thermometer as you’d expect a guy whose dedicated his career to it would be. Here’s the tech he says makes the ThermoScan 7 so special.

A pre-warmed tip “reduces the difference between the target temperature and the thermopile (sensor) and therefore reduces the potential error caused by this difference.” In other words, the smaller the gap between the temperature in the room (therefore the temperature of the sensor) and the target temperature in the ear canal, the more accurate the reading will be. And since the ear canal even at a normal temperature (in the high 90s) will be much warmer than the room (in the 60s or 70s), embedding a heater into the circuitry of the sensor is a great way to reduce noise and shrink the margin of error.

Speaking of sensors, the ambient sensors on this thermometer are just as important as the proprietary one in the pre-warmed tip. They collect data on the ambient temperature in the room, which means the built-in proprietary algorithms have the data they need to operate properly.

First, they convert the infrared energy measured by the principal sensor into a temperature reading. Then, they convert that temperature reading into what’s called the oral equivalent temperature that’s a more accurate reflection of your kid’s temperature because it takes into account the data measured by the ambient sensors.

The Design

The thermometer is calibrated to be used with hygienic probe covers, and it won’t take a temperature reading without them. That’s just one of the many clever touches incorporated into the design. McDuffie puts it more intelligently and charitably, saying “there’s a lot of things we did to the design in order to really simplify the use case scenario.”

“The top has been shaved down so when you’re going into the ear canal the speculum is aligned so you can see where you’re going,” he says.

And in addition to providing a clear view of the ear canal, the angle of the tip relative to the device means it’s comfortable to use and that the temperature taker’s finger naturally falls on the measurement button, no awkward reaching required.

“We have it set up so you can see the screen…so you can actually read it while using it,” he says, which seems obvious but is far from universal. There’s also an audible alert when the unit is done collecting data and an ExactTemp light on top of the unit that’s impossible to miss when it lights, informing the parent that the thermometer isn’t properly positioned.

The Testing

Testing is built into the design process from beginning to end. “During product design and development, we validate the performance of product components and design, such as sensors, boards (computer chips), layouts and algorithms,” McDuffie explains. Here’s how it works.

Lab testing is the first step, where “high precision blackbody systems” put the thermometer through its paces “at a full range of target temperatures, changing humidity, and room temperatures.” Essentially, these systems allow Braun scientists to know what the thermometer’s sensors should be picking up, which means they know if it’s correct or not.

Once it passes these tests, the thermometer is ready for multiple clinical studies that follow ASTM and FDA guidelines. “The clinical study includes patients from newborns through adults and requires a range of temperatures from normal to febrile,” McDuffie explains, making a convincing case that the ThermoScan 7 will be accurate in any situation you might want to use it in.

After the design is approved, it’s time for manufacture and the factory testing that goes along with it, part of what McDuffie deems “the largest and strictest manufacturing setup in the world.”

“It takes over 24 hours just to go through the process to produce one infrared thermometer,” a process that includes further blackbody tests in a variety of ambient conditions that is “as stringent or more as thermometers used by doctors.” Every single thermometer that makes it to stores has made it through this process, as have the probe covers at the Chicago-area factory where they are made.

So when you buy a Braun thermometer, you’re buying a high-tech, nearly foolproof device that’s the product of thousands of hours of design and testing and years of expertise. Opting for a Braun is one is one of the easier decisions parents have to make, which means more time to enjoy the experience.

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