Using an insulin pump can be life-changing, offering flexibility and freedom that other therapies can’t match. But let’s be honest: it’s not always a smooth ride. One of the most common sources of frustration for pump users is infusion set trouble. An unexplained high blood sugar, a painful site, or an adhesive patch that just won’t stick can quickly turn a good day into a stressful one.

If you’ve ever found yourself staring at your pump and wondering what went wrong, you are not alone. Effective infusion set troubleshooting is a skill that every pump user develops over time. This guide is here to help you fast-track that learning curve. We’ll cover five of the most common issues with Tandem infusion sets, from occlusion alarms to adhesive issues, and provide practical, easy-to-follow solutions to get you back on track.

1. Unexplained High Blood Sugar (The “Is This Thing On?” Problem)

This is perhaps the most frequent and frustrating issue. You’ve eaten a meal, bolused correctly, but your blood sugar just keeps climbing. You give a correction dose, then another, and still, nothing happens. It can feel like the insulin is vanishing into thin air.

Possible Causes:

• Bent or Kinked Cannula: This is the most likely culprit. A soft cannula can bend or kink upon insertion or if it gets bumped, completely blocking insulin flow. It won’t always trigger an occlusion alarm.
• Site Failure: The tissue at the infusion site may have become inflamed or developed scar tissue (lipohypertrophy), preventing it from absorbing insulin properly. This is common on the third day of wearing a set.
• Air Bubbles in Tubing: Small air bubbles in the cartridge or tubing can create a gap in insulin delivery. While a tiny bubble is usually harmless, a larger one can prevent a full bolus from reaching you.

Solutions:

• The Golden Rule: When in Doubt, Change It Out. If you’ve had a stubborn high for more than a couple of hours and corrections aren’t working, don’t keep throwing insulin at the problem. The safest and most effective solution is to change your entire infusion set and move to a fresh site in a different body area (e.g., from your abdomen to your upper buttock).
• Give a Manual Correction: While you are changing your set, use an insulin pen or syringe to give a correction dose. This ensures you get the insulin you need while bypassing the potentially faulty infusion site.
• Inspect the Old Site: When you remove the old set, look at the cannula. Is it bent into a “J” shape? This confirms a kinked cannula was the issue. If the site is red, swollen, or bloody, that’s also a sign it was time for a change.
• De-Bubble with Care: During your next cartridge change, be meticulous. After drawing insulin into the syringe, point it upwards and flick it to get all bubbles to the top before carefully pushing them out. When filling the cartridge, follow Tandem’s instructions precisely to remove air. As one user discovered, watching the official videos and following every step, like holding the pump upright when filling tubing, can make a big difference.

2. Occlusion Alarms

Your pump screen flashes with an “OCCLUSION” alert, and the loud alarm tells you insulin flow is blocked. While this alarm can be annoying, it’s a critical safety feature.

Possible Causes:

• A kinked cannula or tubing.
• Pressure on the infusion site (e.g., from a tight seatbelt or lying on it while sleeping).
• A clog at the cannula tip from crystallized insulin or a small blood clot.

Solutions:

• Check the Tubing First: Before you do anything else, check the entire length of your tubing for any visible kinks or twists. Sometimes simply straightening it out can resolve the alarm.
• Relieve the Pressure: If you’re sitting or lying in a way that puts pressure on your site, shift your position.
• Attempt to Resume Insulin: Follow your pump’s on-screen instructions to try resuming delivery. If the occlusion alarm happens again right away, it’s a clear sign of a more persistent blockage.
• Change the Site: A recurring occlusion alarm is a non-negotiable signal to change your infusion set. There’s a blockage at the cannula that can’t be cleared, and no more insulin will be delivered through that site.

3. Adhesive Not Sticking

There’s nothing worse than the feeling of an infusion set peeling off, especially when you’re being active or it’s hot outside. Keeping that little adhesive patch secure for three days can be a challenge.

Possible Causes:

• Oily or moist skin from lotions, soaps, or sweat.
• Placing the set on a very hairy area.
• Placing the set on a part of the body that bends and stretches a lot (like directly over a joint or muscle crease).

Solutions:

• Prep the Skin: A good foundation is everything. Clean the area with an alcohol wipe and—this is key—let it dry completely before inserting your set. The skin should be clean, dry, and free of any oils or lotions.
• Try an Adhesive Enhancer: Products like Skin-Tac™ can be a game-changer. It’s a liquid adhesive “wipe” that you apply to the skin before insertion. It creates a tacky barrier that helps the set’s adhesive stick like glue.
• Use an Over-Patch: Many companies make specialized over-patches designed to go over your infusion set. These provide an extra layer of security and can be especially helpful for swimming, sports, or if you’re a restless sleeper. You can even cut a hole in the middle of a larger medical tape (like Hypafix or Tegaderm) to create your own.
• The “Safety Loop”: After inserting your set, make a small loop with the tubing near the site and tape it down. This way, if the tubing gets snagged on a doorknob, the tape takes the force instead of ripping the set directly out of your skin.

4. Pain, Bleeding, or Bruising at the Site

While a tiny pinch during insertion is normal, an infusion site shouldn’t be painful to wear. Pain, significant bleeding, or bruising are signs that something isn’t right.

Possible Causes:

• Hitting a Blood Vessel: A small amount of blood on insertion is common, but a “gusher” means you’ve likely hit a larger capillary. A site with a lot of bleeding may not absorb insulin well.
• Hitting a Muscle or Nerve: This can cause a sharp or persistent aching pain. It’s more likely if you’re very lean or using a cannula that’s too long for that body area (e.g., a 9 mm cannula on a lean arm).
• Skin Irritation or Allergic Reaction: Redness, itching, and inflammation can be a reaction to the cannula material or the adhesive.

Solutions:

• Don’t Be a Hero: If a site is genuinely painful, just change it. It’s not worth the discomfort or the risk of poor absorption.
• Apply Pressure: If you have a bleeder, remove the set and apply firm pressure with a sterile gauze or cotton ball for a few minutes until it stops.
• Re-evaluate Your Set: If you frequently experience pain or bruising, you may need a different type of infusion set. If you use a 90-degree set (like AutoSoft 90/XC), try an angled set (like AutoSoft 30 or VariSoft) which inserts at a shallower angle. If you often hit muscle, consider a shorter 6 mm cannula instead of a 9 mm one. For some, the spring-loaded action of the auto-inserters can cause bruising, and they have more success with the manual insertion of a VariSoft or TruSteel set.
• Consider a Steel Set: If you have a suspected allergy to the plastic in soft cannulas, the TruSteel infusion set is an excellent alternative.

5. Difficulty with the Infusion Set Itself

Sometimes the problem isn’t with your body, but with handling the device. Many users who switch from other pump systems find Tandem’s supplies have a learning curve.

Possible Causes:

• Difficulty Disconnecting/Reconnecting: Some users find the “pinch” mechanism on the AutoSoft 90 connector hard to operate.
• Trouble with the Paper Backing: On the AutoSoft 90 and XC sets, the spiral paper backing can sometimes tear, leaving half the adhesive covered.

Solutions:

• Practice with an Old Set: If you’re having trouble disconnecting, practice on a set you’ve already removed. Get a feel for how and where to squeeze the tabs to get a clean release.
• Try the AutoSoft XC: The AutoSoft XC was designed specifically to address the disconnection issue. Its larger grip is almost universally preferred by those who have tried both sets. If you’re struggling with the AutoSoft 90, ask your supplier for XC samples.
• Be Gentle and Deliberate: When removing the paper backing or the blue needle cover, go slowly. As one experienced user recommends, “spin the blue cover until it feels loose, then you gently lift it off.” Pulling too aggressively can dislodge the cannula from the inserter needle before you even begin.

Your Next Steps

Mastering insulin pump therapy is a marathon, not a sprint. Every challenge is a learning opportunity. Don’t be afraid to experiment with different infusion sets and site locations to find what works best for you. Keep a “backup kit” with insulin pens or syringes handy, and always remember the golden rule: when in doubt, change it out. Talk to your diabetes educator or healthcare provider about your struggles; they can provide samples and expert guidance to help you solve any persistent problems.