September 22, 2023

Main Differences Between the FSL2 vs. the FSL3

Learn the key distinctions between Abbott's latest continuous glucose monitoring systems in this guide with US MED.


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FSL2 reader and FSL3 reader

Home / Living with Diabetes / Main Differences Between the FSL2 vs. the FSL3

Everyone with diabetes should take diabetes management seriously, but successfully keeping this condition under control can be tricky. Along with countless other annoyances, many people with diabetes need to check their glucose levels multiple times per day. Historically, this has meant going through time-consuming, painful fingerprick tests.

But now, there’s a better way: using a continuous glucose monitoring (CGM) system. Though a CGM can’t eliminate your need for fingerprick tests, these products can significantly reduce your reliance on these tests—and the time you’ll spend drawing and measuring blood during an average day. Instead of painful fingerpricks, most CGM systems use a small sensor worn on a user’s body to provide 24-hour glucose updates.

Abbott is one of the world’s leading CGM manufacturers, and their two most advanced products in this category are the FreeStyle Libre 2 and FreeStyle Libre 3 systems. Are you wondering what factors set these devices apart? In this article, we’ll outline the key differences between the FreeStyle Libre 2 system (FLS2) and the FreeStyle Libre 3 system (FLS3). 

What Is New to the FSL3 vs. FSL2?

In some ways, the FreeStyle Libre 2 and FreeStyle Libre 3 systems are quite similar—but these devices are far from identical. The FSL2 and FLS3 differ in terms of their:

Sensor Sizes

The FreeStyle Libre 2 system’s sensor was relatively unobtrusive, but the FreeStyle Libre 3 system takes things to the next level. The newer CGM’s sensor is roughly the size of two U.S. pennies, one stacked on top of the other. That means it’s not just small—it’s the smallest, thinnest CGM sensor ever made.*

Scanning Requirements

Using a CGM system is more convenient than taking a fingerprick test, but that doesn’t mean every product in this category is equally easy to use. For example, some CGMs require users to get readings by manually scanning their sensors, while others don’t.

That’s how the FSL2 system works—if you use this system, you won’t be able to get glucose updates without a scan. On the other hand, the FSL3 system automatically sends glucose readings to your reader or compatible smart device.

Application Procedures

Early FreeStyle Libre products (up to and including the FreeStyle Libre 2 system) required users to connect their sensor to an applicator before they could apply it. That’s not the case for the FreeStyle Libre 3 sensor, which boasts a single-step application process.

Overall Accuracy

Mean absolute relative difference (MARD) is a commonly used measurement of accuracy for CGMs—the lower this number, the more accurate the device in question. Based on a press release issued by Abbott, the FreeStyle Libre 3 system has a MARD of 7.9 percent. In contrast, the FreeStyle Libre 2’s MARD has been measured at 9.2 percent, making the newer CGM system the better choice for people seeking the most accurate glucose readings possible.

Coverage Requirements For the FSL3 vs. FSL2

Both the FreeStyle Libre 2 system and the FreeStyle Libre 3 system are covered by Medicare Part B as durable medical equipment, as is the case for their associated sensors. However, you’ll need to meet some coverage requirements before Medicare will pay for these devices.

In order to qualify for FreeStyle Libre system coverage under Medicare, patients must:

  • Have diabetes. If you don’t have diabetes, you don’t need to use a CGM system. 
  • Regularly check their blood sugar. Diabetes patients have to test their blood glucose at least four times daily to qualify for coverage for one of these devices.
  • Use insulin. You don’t need to be on insulin to use a FreeStyle Libre system. However, Medicare will only cover these CGMs if you inject insulin at least three times per day.
  • Have approval from a physician. To qualify for FSL2 or FSL3 coverage through Medicare, you’ll need an official prescription for this equipment and a statement saying it’s a medical necessity.

Get Your FreeStyle Libre System Today

By now, you’ve considered the differences between the FLS2 and FLS3, picked the right CGM system for your needs, and determined whether or not you’ll be able to get your CGM covered by Medicare. Still, there’s one more thing you’ll need to do before buying a CGM system—you’ll need to find a trustworthy supplier for these products.

At US MED, we offer a broad selection of CGMs, including the FreeStyle Libre 2 and FreeStyle Libre 3 systems. You’ll also be able to buy sensors for your CGM right here, along with insulin pumps and “traditional” diabetes testing supplies. No matter what you purchase from US MED, you’ll benefit from free priority shipping, support from skilled diabetes specialists, and countless other perks. Take a look at what we have in stock today!

*Among patient-applied sensors. Data on file, Abbott Diabetes Care

The FreeStyle Libre 2 or 3 cannot completely replace fingerstick tests. These tests are required to confirm any low or high sensor readings and when sensor readings do not match your symptoms.

Shirley DeLeon Certified Diabetes Care & Education Specialist

Medical Review by Shirley DeLeon, Certified Diabetes Care and Education Specialist

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