Tandem t:slim X2 insulin pump with Basal-IQShare on Pinterest
Image from Tandem Diabetes Care

One of the most advanced diabetes devices available is the touchscreen insulin pump by Tandem Diabetes Care. Its smart software predicts glucose levels and adjusts insulin automatically as needed.

The first version of that technology is known as Basal-IQ, a software feature built into the t:slim X2 insulin pump to help prevent hypoglycemia and keep glucose levels in range.

This received regulatory approval from the Food and Drug Administration (FDA) in June 2018. It’s been available since that summer.

The much-anticipated system connects the touchscreen t:slim X2 pump with the latest Dexcom continuous glucose monitor (CGM) to provide glucose prediction and automatic insulin shutoff when low glucose is predicted.

It capitalizes on the t:slim X2’s ability to be remotely updated from home. This means new features can be incorporated without needing to buy a whole new pump every time a new function or feature is introduced.

Here, Healthline sums up the features, pros and cons, user experience, and pricing details of this partially automated insulin delivery (AID) system.

(Note: Tandem Diabetes Care has an even more advanced AID system known as Control-IQ, but some users prefer the features of Basal-IQ. Read on to learn more.)

Tandem Basal-IQ is a system that integrates the Tandem t:slim X2 insulin pump with the Dexcom G6 CGM and the proprietary Basal-IQ algorithm designed to help keep blood sugars in range. The system can automatically shut off insulin delivery for limited periods if low blood glucose is predicted.

It does this in two cases:

  • when you go below 70 mg/dL
  • when its algorithm predicts you will go below 80 mg/dL within the next 30 minutes

For both situations, Basal-IQ automatically resumes insulin delivery when your glucose level begins to rise again. It uses three of the past four readings to trigger that auto-shutoff. The main screen displays red swatches to indicate when and for how long Basal-IQ has shut off your insulin delivery.

Users can choose whether they want alerts to sound each time insulin delivery is suspended. This allows you to have Basal-IQ in the background, with fewer alerts and alarms to disrupt your day to day. For some people, this can help address diabetes device fatigue.

Pros of Basal-IQ

  • The t:slim X2 insulin pump is very user-friendly. It has a color touchscreen that’s easy to read.
  • The system connects directly to the Dexcom G6 CGM and displays real-time glucose levels and several hours’ worth of past data.
  • It provides protection from dangerously low glucose by automatically turning off insulin when you go below 70 mg/dL, or when the system predicts you’ll drop below 80 mg/dL in the next half hour.
  • You can turn off most notifications and alerts so it operates in the background.
  • It has a mobile app to view insulin pump and CGM data, and easily share reports with your healthcare team.

Cons

  • It only addresses low glucose levels, not high glucose levels.
  • It relies on the Dexcom G6, which means inaccurate readings or a faulty CGM sensor can impact Basal-IQ use.
  • The t:slim X2 insulin pump has an appealing modern design but has several practical drawbacks that can hamper one’s use.
  • You must buy both Tandem insulin pump and Dexcom CGM supplies, meaning it can be very expensive, even with insurance coverage.

The t:slim X2 insulin pump is the core of the system. It offers the only color touchscreen available on any insulin pump.

It allows you to remotely update the pump from home, just like you can with an iOS or Android smartphone.

This was a first in the insulin pump market. It means you don’t have to buy a new piece of hardware every time some functionality or feature is upgraded.

Tandem’s pumps are unique in using a color touchscreen. For safety reasons, there’s a three-button wake-up and confirmation series required anytime you want to use it.

You need to tap on the touchscreen’s 1-2-3 buttons when displayed to unlock it. There’s usually at least one confirmation message for whatever task you are trying to accomplish when using the pump — whether giving yourself a mealtime or “correction” dose of insulin, entering a blood sugar reading or carb amount, or manually turning off insulin delivery for a swim or other activity.

Because this system is integrated with the Dexcom G6 CGM (which you wear on your body separately), the pump display also shows a CGM icon and data.

You can press the silver “T” button on the top of the screen to wake it up and see the full-color CGM status screen for glucose data, battery and transmitter status, as well as insulin on board (IOB, or the active insulin) and the volume of insulin inside the pump at the time.

The default view of CGM data is 3 hours, but you can also scroll through 1-, 6-, 12-, and 24-hour trace screens without needing to repeat the three-button unlocking sequence.

While many people in the diabetes community have described the Tandem t:slim X2 as an easy-to-use device compared with others, there are minor issues that some find irritating when using this insulin pump:

  • Possible leakage: The little pig-tail part of said tubing is unique to Tandem. For years, people have complained that the twist-and-connect design leaves open the possibility of leaking insulin or introducing air bubbles into the tubing.
  • Multiple confirmation alerts: To unlock and use the touchscreen, you have to go through a confirmation screen each time. People with larger fingers or difficulty with finger movements might miss their target. Thanks to a “three strikes rule,” where the screen locks if you touch an inactive part of it three times in a row, you may need to start over by unlocking it and hitting all the buttons again.
  • Fixed alarms: Several pump alarms cannot be silenced or turned off, including “empty cartridge.” So, if you have a tendency to take a break before you start a new pump session, this alarm will constantly beep without any option to quiet it.

The CGM that powers Basal-IQ is the Dexcom G6. It’s the latest generation of that company’s device as of mid-2022.

To use Basal-IQ, you need to purchase Dexcom G6 supplies and Tandem pump supplies separately.

The G6 leads the CGM market. It gets high marks for comfort, accuracy, and ease of use.

It is FDA-approved for direct insulin dosing decisions, meaning there’s no need to take a confirmatory finger-stick glucose test before making insulin dosing decisions. It also self-calibrates, but you do still have the ability to manually calibrate it by plugging in a finger-stick result if you want to.

The Dexcom G6 sensor is labeled to last on the body for 10 days. As a Basal-IQ user, if a sensor fails early before the 10-day mark, you can contact either Dexcom or Tandem support to get a replacement sensor.

Note that some users have reported that the Bluetooth connection between the t:slim X2 insulin pump and the Dexcom G6 transmitter isn’t always reliable. Lost connections seem to sometimes happen when the insulin pump is positioned on the opposite side of the body as the Dexcom G6.

Tandem first launched its mobile app in 2020. It allows users to see their insulin pump and CGM data and view many features of the Tandem system they’re using (Basal-IQ or the more advanced Control-IQ).

A new version of the app has been available since early 2022. Some people use their iOS phones to directly dose insulin from the phone app rather than needing to dose from the insulin pump directly.

Basal-IQ also works with Tandem’s t:connect software for data analysis and data-sharing. You can share information with your diabetes care team. They can log in directly to your account (with your permission) and view your data to help in your diabetes management.

Of course, what you really want to know is how well this partially automated system works to manage blood sugars.

Clinical study findings are largely positive and impressive.

A 2018 study showed that the predictive capability significantly reduced hypoglycemia without rebound highs for both adults and children with type 1 diabetes.

Notably, that research showed 99% of the study participants finished the study. That’s a big difference compared with the competing system at the time, which saw fewer people finishing the clinical trial because of accuracy and usability concerns about that competing technology.

In a 2019 study, researchers looked at data voluntarily submitted by more than 5,000 Basal-IQ users. They found that most of them reported high levels of satisfaction, trust, and usability. It also helped them sleep better and achieve better diabetes management overall.

Many people in the diabetes community have shared their thoughts through the years about Basal-IQ.

One of those is Connecticut mom Samantha Merwin, whose son Logan participated in the Basal-IQ clinical trials. She said it was “truly a miracle for us,” particularly overnight when her son could wake up and see how many times the system had suspended his insulin while he was sleeping.

Another early adopter, Brian Mozisek in Texas, said he particularly liked how Basal-IQ offered him an ability to prevent low blood sugars during his high levels of activity and exercise.

Mozisek said it helped him more aggressively tweak his settings and watch for higher blood sugars that Basal-IQ can’t address.

Basal IQ is ‘mostly crazy wonderful’

As a longtime type 1 myself who’s used the Tandem technology, I observed that during my time using Basal-IQ, it effectively cushioned the blow of hypoglycemia without eliminating lows completely.

Thanks to the predictive auto-suspend feature, I’ve avoided plummeting into a situation where I need help. This is huge, and I’ve noticed that with continued use, Basal-IQ has started giving me more confidence to sleep through the night without fear of dangerous, severe hypos.

Because I don’t feel the symptoms of lows much of the time overnight (aka hypoglycemia unawareness), this is a big deal for my wife and me.

Another glowing review comes from longtime type 1 Wil Dubois in New Mexico, who described it as “crazy wonderful most of the time.”

When first test-driving the system, Dubois found that Basal-IQ added a whole new level of CGM integration and diabetes control that he’d never seen before.

Dubois reported that for him, the system was “pretty remarkable” and “crazy wonderful” at keeping his blood sugars in check. However, he did note that it didn’t always catch “coasting lows,” the ones where you’re steadily dipping lower over the course of several hours.

Complaints about Tandem t:slim X2 technology

Of course, every diabetes device has its drawbacks. Here are some that have been flagged by seasoned Basal-IQ users:

False lows: The Dexcom G6 — just like any CGM sensor — can generate inaccurate readings at times, such as if you’re sleeping on the sensor and triggering what some folks commonly call a “compression low.” This can result in Basal-IQ falsely thinking it needs to shut off insulin delivery. The sensor reading will readjust to accuracy after you take the pressure off it.

Repeat data entry: You must manually enter CGM sensor glucose values into the pump before delivering any correction boluses for higher blood sugars. On one hand, it makes sense since Basal-IQ only adjusts insulin for lower glucose levels. But it’s a bit of a head-scratcher since the t:slim X2 is connected by Bluetooth to the Dexcom G6 CGM and has full access to that data.

Low dosing lock: If your sugars are low, Basal-IQ has suspended insulin, and you want to eat, you can’t layer on a dose of insulin for the carbs you’re consuming. Yes, you may currently be low or at risk of going low. But if you’re about to eat a banana split, it would be a good idea to deliver some insulin to cover it to prevent a rebound high.

Snooze mode cancellation: If you’re not interested in using Basal-IQ’s predictive capabilities, you can scroll to an option to turn off the auto-shutoff feature for a period of time. But if you had started an extended bolus before activating this snooze mode, Basal-IQ will also cancel any remainder of that extended bolus.

No scheduling profiles: There’s no automatic way to switch between basal (background insulin) profiles. This means if you’ve set up a special weekend profile, you cannot set it to kick in at midnight on Fridays. Rather, you have to remember to activate it manually.

Tandem’s newer and more advanced Control-IQ system can adjust insulin delivery for both low and high glucose levels. It offers a number of other features to improve one’s glucose time in range. That system was FDA-approved in 2020.

What’s important to know is that while both Basal-IQ and Control-IQ use the foundational t:slim X2, you cannot go from Basal-IQ to Control-IQ and then go back. Regulators don’t allow for that.

This means that if you have a Basal-IQ pump and then update it to the more advanced software, you’re unable to revert to the older Basal-IQ version.

There are pros and cons to both systems. Some users have shared that they were less happy with Control-IQ than they were beforehand because Basal-IQ offered more flexibility in fitting with their lives.

Make sure to do your research before deciding on one or another. You can read a full review of Control-IQ here.

Affordability is one of the big drawbacks of any insulin pump, especially one that’s tied to using CGM data.

You can purchase the t:slim X2 insulin pump on its own, but the whole point of Basal-IQ (and Control-IQ) is having access to the automation, and that requires you to also have a Dexcom CGM.

That means you must buy not only the Tandem t:slim X2 and supplies but also the Dexcom G6 system. It can be quite costly, even with insurance.

Without insurance, the Tandem t:slim X2 pump alone has a retail price tag of $4,000. With private insurance, some plans will cover almost 80% of this cost.

For the Dexcom G6 CGM, when you factor in the 10-day sensors and the 90-day transmitters, our estimate of the annual cost of use is $6,000 per year, or $500 a month.

Make sure to check on timely discount programs the manufacturers may offer. You can also check with your own insurance for coverage specifics.

The Tandem t:slim X2 pump needs to be purchased directly from the manufacturer.

The Dexcom CGM and its supplies can be purchased through third-party distributors like Edgepark or at retail pharmacies across the United States, including CVS, Rite Aid, and Walgreens.

Here’s how to get started on the Tandem technology:

  1. Talk with your endocrinologist or diabetes care team to determine whether an insulin pump, CGM, and particularly the Tandem devices, may be best for you.
  2. Check with your insurance to determine coverage and pricing.
  3. Contact Tandem Diabetes Care directly or through your doctor’s office to begin the process of starting a new system. Tandem will need to contact your doctor’s office to get a prescription, as well as to determine with your insurance company specific coverage requirements and pricing that apply. This can take several days to weeks, depending on many factors.
  4. After pricing and prescription aspects are finalized, Tandem will work with you or your supply company to get the needed supplies sent to you.
  5. Once you receive the Tandem device, you’ll work with a company trainer or your diabetes care team to determine appropriate settings to program into the device. They will also work with you to learn the new system, including sending helpful videos and resources, like the user manual and training guides.
  6. Diabetes devices like the Tandem t:slim X2 and Basal-IQ are not always quick learns; they may take some time to get used to. Initial settings may vary as you use the system, and some of the ways you currently manage diabetes may need to change. Just remember: Be patient and allow yourself time to learn the system. But do remember to keep any return policy details in mind, just in case.

When to contact your doctor

You can always talk with your doctor and diabetes care team about your goals for glucose levels and what diabetes technology tools might work best for you.

But meeting with your diabetes care team and endocrinologist may be especially helpful if you’re experiencing any trends in higher or lower glucose levels, particularly if you experience any hyperglycemia symptoms that might signal diabetic ketoacidosis (DKA).

Insulin pumps and CGM technology aren’t for everyone. Existing devices also offer different options, so make sure to talk with your care team about what might work best and how they feel about the technology for you.

By mid-2022, the Medtronic MiniMed 770G and the Insulet Omnipod 5 systems are available in the United States as the two other companies making automated insulin delivery devices. Tandem has also launched its more advanced Control-IQ system since Basal-IQ first launched.

Here’s a look at those three other systems:

Medtronic MiniMed 770G: This device combines a Medtronic insulin pump and Medtronic CGM with a controlling algorithm and apps that allow you to track your glucose levels and see pump data. It addresses both high and low blood sugars, like the Tandem Control-IQ version. One advantage may be that Medtronic is the only company that makes both insulin pumps and a CGM, so you only have to deal with a single manufacturer. The downsides are that Medtronic pumps are more “old school” design with no touchscreen. Many reviewers say their CGM is far less comfortable to wear than the Dexcom.

Omnipod 5: As the only tubeless patch pump available in the United States, this system has been available since early 2022. This is one of the most advanced systems on the market. It includes a customizable target for glucose goals rather than a fixed target like the other systems.

Tandem Control-IQ: This has been available in the United States since 2020. It’s a more advanced system than Basal-IQ because it automatically adjusts insulin for both low and high blood sugars.

Here’s a quick glance at how each device compares based on product information and clinical research.

Basal-IQControl-IQMiniMed 770GOmnipod 5
Designhorizontal
with color touchscreen
small horizontal pump
with color touchscreen
vertical design,
smartphone-size,
screen buttons
only tubeless
patch pump in U.S.
CGM connectionDexcom G6
(10-day sensors);
finger-stick calibrations not required
Dexcom G6
(10-day sensors);
finger-stick calibrations not required
MiniMed Guardian 3
(6–7 days);
requires 2–3 finger-stick calibrations per day
Dexcom G6
(10-day sensors);
finger-stick calibrations not required
Warmup2 hours for CGM data warmup2 hours for CGM data warmupno CGM data during 2-hour warmup; 48-hour warmup before auto mode starts2 hours for CGM data warmup, but still in auto mode
Set target112.5 mg/dL120 mg/dLcustomizable
110–150 mg/dL
Suspends insulinyesyesyesyes
Auto correctionsno60% of programmed rate to 110 mg/dL targetnoyes, but more frequent smaller auto microboluses
Phone appyes, with limited pump controlyes, with limited pump controlyes, but no pump controluses smartphone app or separate controller
Special modesnoexercise +
sleep modes for higher glucose targets, auto-corrections
manual and auto modesactivity feature for higher glucose target and reduced basal

Beyond FDA-regulated insulin pump systems, there are some other options that automate insulin delivery aspect:

Smart insulin pen systems: The Bigfoot Unity AID system received FDA clearance in May 2021. This system integrates an insulin pen with a CGM. It provides many of the advantages of a connected system to users who manage their diabetes with multiple daily injections (MDI therapy).

DIY devices: Some tech-savvy people with diabetes have chosen to build their own automated insulin systems using the Dexcom CGM, certain insulin pump models, and an open source algorithm (either OpenAPS or Loop). Once set up, these DIY setups work almost exactly like the Tandem, Medtronic, or Omnipod systems, but they do require a lot of setup time and trial and error, and their use is not FDA-approved.

How much does the t:slim X2 insulin pump cost?

Insulin pumps and supplies can be expensive, but many insurance plans cover this technology.

Without insurance, the Tandem t:slim X2 pump alone has a retail price of $4,000. With private insurance, some plans will cover almost 80% of this cost.

You’ll also need to buy supplies each month, including infusion sets and insulin cartridges. These supplies can range from $70 to $400, depending on your needs and insurance coverage.

With Tandem Basal-IQ, you will also need to separately buy the Dexcom G6 CGM supplies. This includes the 10-day sensors and 90-day transmitters, which may cost around $6,000 per year.

What insulin does the t:slim use?

The Tandem t:slim X2 insulin pump works with most of the available rapid-acting insulin brands in the United States, including Humalog and Novolog.

Some people also use Apidra and Fiasp with their insulin pump, though research is not as clear on whether that is advised.

How long does the t:slim insulin pump last?

The t:slim X2 insulin pump has a 4-year warranty. The warranty may depend on your insurance company policy, in what they consider “new” when replacing an insulin pump.

The life span of this insulin pump can depend on how active you are. If it is damaged, Tandem Diabetes Care and most insulin pump companies offer loaner programs for quick replacements.

How often do you change t:slim insulin pump sites?

Medical professionals advise changing the t:slim X2 insulin pump sites every 2 to 4 days. This involves inserting a new infusion site on a different spot on your body, as well as filling a new cartridge with insulin and installing that into the pump.

You will also need to fill the new plastic tubing with at least 10 units of insulin, and then fill the cannula in your skin with a small amount of insulin.

Most people who have tried Basal-IQ say that Tandem has a real winner here. But it’s important to keep in mind that this system only addresses half of the glucose management equation: It only reacts to low blood sugars, not highs.

Using a partially automated system like Basal-IQ may be daunting for some people with diabetes, especially those who have lived with this condition for a long time. They may feel like they’re being forced to give up their own control of their insulin regimen.

Yet, after giving it a chance and learning some of the ins and outs of how Basal-IQ works, many people have found that this is just the option they need to protect from dangerously low blood sugar events.

For some, the online training modules offered by Tandem may be key to successful use.