Insulin pumps like the Tandem t:slim X2 and Mobi give users incredible freedom in diabetes management—but infusion set issues can still cause real frustration. From unexplained highs and alarm beeps to painful sites or adhesion trouble, it’s normal to hit snags with your set. The good news? Most infusion set problems are solvable, and strategies used by other Tandem users, paired with real troubleshooting guidelines, can make a big difference.

This guide will walk you through infusion set troubleshooting for the most common Tandem infusion set problems—including occlusion alarms, kinks, adhesive problems, and site rotation. Drawing on user experiences and clinical advice, it offers specific, practical steps for each challenge.

1. Persistent High Blood Sugar? – Check Your Set

The scenario: You bolus, but your blood sugar stubbornly climbs. You try again, still high.

User insights:

• Many Tandem users (especially with AutoSoft 90) report high BGs due to bent or kinked cannulas, often on day 2-3 after insertion.
• Bent cannulas may NOT trigger an occlusion alarm.
• Visible insulin droplets inside the set dome after removal can indicate a kink or blockage.

Key causes:

• Kinked or bent cannula (most common, especially with Teflon sets)
• Clogged cannula (by blood or tissue)
• Air bubbles in tubing (especially if cartridge was not properly filled or primed)
• Scar tissue or poor absorption at an overused site

Actionable solutions:

• When in Doubt, Change it Out: If your high doesn’t resolve with a correction bolus, replace the infusion set and move to a fresh body area—even if the pump didn’t alarm.
• Manual Correction: Use an insulin pen or syringe for a correction if you’re worried insulin isn’t being absorbed.
• Inspect Your Old Set: Look for kinks, bends, blood, or blockage. If you see these issues, consider trying a steel needle set like TruSteel, which can’t kink and can be reinserted if accidentally pulled out.
• Learn from Each Set: If possible, check for visible insulin in the dome or examine the removable needle’s shape after insertion. Adjust your technique if you notice frequent bending, and try different cannula lengths or angled sets if you’re lean, muscular, or active. Many users have success with 6mm cannulas or the VariSoft, which offers an angled, manually inserted option.
• Cartridge Filling: Take extra care when filling/prepping your Tandem cartridge. Expel bubbles slowly, keep the pump upright, and follow official videos for bubble-free prep.
  

2. Occlusion Alarms: What to Do

The scenario: You get the dreaded “OCCLUSION” alert from your pump, and insulin delivery stops.

Causes:

• Kinked tubing or cannula
• Blocked cannula tip (from crystallized insulin or blood)
• Excess pressure on the insertion site (tight clothing, sleeping position)

Official troubleshooting:
(Tandem’s stepwise guide)

1. Disconnect the tubing from your infusion site.
2. Tighten connections. Twist the t:lock connector clockwise.
3. Check tubing and site for kinks, blockages, or bubbles.
4. Bolus test (disconnected): Deliver 5 units into the air.

• If no alarm: Blockage is likely at the site—change your set.
• If alarm persists:
• Disconnect tubing from cartridge, try bolus test again.

• If no alarm: Tubing was at fault, replace set/tubing.
• If alarm recurs: Cartridge/blockage, replace cartridge.

Prevention tips:

• Use room temperature insulin and fill the cartridge carefully.
• Prime tubing and cartridge fully.
• Rotate sites and avoid areas with scar tissue or bruising.
• Don’t overfill cartridges or re-use insulin.
  

3. Adhesive Not Sticking? – Get Better Security

The scenario: Your set starts peeling off before the third day, maybe after swimming, sweating, or a restless night.

User tips:

• The adhesive area on some Tandem sets (especially soft Teflon ones) is smaller than other brands. Some note that AutoSoft XC is easier to disconnect without disturbing the site.

Actionable solutions:

• Prep the Skin: Clean with alcohol and let dry completely. Remove lotions or oils.
• Shave Hairy Areas: Use a clean razor and shave with (not against) hair growth before insertion.
• Enhance Adhesion: Try adhesive wipes (Skin Tac, IV Prep) or barrier sprays. Let any primer product dry before insertion.
• Use Over-Bandages: Products like Tegaderm, Hypafix, or specialty over-patches can help. Cut a hole for the connector as needed.
• Try “Safety Loops”: Tape a loop of tubing to your skin near the insertion site; this absorbs the pull if you catch your tubing on something.
  

4. Pain, Bleeding, or Skin Reaction at the Site

The scenario: Insertion hurts, there’s significant bleeding or a bruise, or you see a rash or redness.

Causes:

• Hitting a blood vessel or muscle (more common with long/straight cannulas in lean users)
• Allergic reaction to cannula material or adhesive
• Site overuse or poor rotation

Actionable solutions:

• Don’t Tough It Out: If it hurts, remove and try another site or angle. Pain signals poor absorption and possible tissue damage.
• Try Different Sets: If you have repeated issues, switch cannula lengths. Manual (VariSoft) or steel sets may be more comfortable and reliable for some.
• Treat Bleeding: Remove the set and apply gentle pressure with a clean tissue.
• Manage Irritation: Use a barrier wipe or underlay for skin protection before inserting the set; try TruSteel for known plastic allergies.
  

5. Master Site Rotation – Avoid Scar Tissue

Best practice:

• Routine site rotation is crucial. Repeated use of the same area leads to scarring and poor insulin absorption. Divide your abdomen (or other site) into quadrants and cycle locations.
• Place each new site at least one inch from the last. Let used sites rest for a few weeks before using them again.

User note:
Sites like the abdomen, upper buttocks, upper thighs, and back of upper arms are all possible, just check with your provider for safety and absorption.

6. Device/Connector Frustrations

Feedback:

• Some users find AutoSoft 90 disconnect difficult, causing accidental bends. AutoSoft XC offers improved grip and easier handling.
• Ongoing adhesive or connection frustration? Ask your supplier for samples of AutoSoft XC, VariSoft, or TruSteel and try which suits you best.
  

Summary: Your Action Plan

Troubleshooting Tandem infusion sets is part science, part personal trial. Armed with these strategies and a willingness to experiment, you’ll gain confidence and reduce disruption. Always keep extra sets and correction tools handy, share your recurring issues with your diabetes care team, and don’t hesitate to try new options.

Remember: If you’re stuck, change it out. And when in doubt, reach out! Your care team and pump supplier want your therapy to succeed.