Ensuring Insulin Pump Safety: The Importance of Accurate Flowrate Testing

For patients with type 1 diabetes, their insulin pump is a lifeline, ensuring they receive the insulin they need with every meal or snack. But what if this essential medical device malfunctions, dispensing either too much or too little insulin? The stakes are high—not just for the patients facing potentially life-threatening situations, but also for the manufacturers dealing with costly repercussions. Bolus testing minimizes these risks, helping to safeguard both patients and manufacturers alike.

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Insulin Pumps in Diabetes Management

Diabetes is a very common condition. According to the International Diabetes Federation (IDF), around 297 million adults aged 20–79 were diagnosed with type 1 or type 2 diabetes in 2021, and this number is expected to reach 700 million by 2045.

Insulin pumps, small electronic devices, play a crucial role in managing diabetes through continuous subcutaneous insulin infusion therapy. They provide fast-acting insulin around the clock (basal insulin) and deliver extra doses (bolus insulin) as needed. Tandem Diabetes Care, the International Diabetes Federation, and the Centers for Disease Control and Prevention (CDC) estimate that 267.3 million people worldwide rely on insulin infusion pumps for diabetes care.

Typically, an insulin pump includes a programmable device, a reservoir filled with insulin by the user, and an infusion set for administering the insulin. These pumps are durable, lasting at least four years. There are also disposable patch insulin pumps available, which stick to the body without using an infusion set.

Using an insulin pump has many benefits: it replaces the need for multiple daily injections, delivers insulin more accurately and precisely, and helps achieve better blood glucose control. They also provide greater flexibility with meals, exercise, and daily routines.

Strict Regulations and Increasing Recalls

The regulatory landscape for insulin pumps is becoming stricter, and for good reason. These devices must perform reliably to prevent serious complications like severe hypoglycemia or uncontrolled blood sugar levels.

In the EU, the new Medical Device Regulation (MDR) has tightened requirements, demanding comprehensive clinical evaluations, stringent quality systems, precise labeling, and robust post-market surveillance. Similarly, the FDA in the US requires insulin pumps to comply with the Quality System Regulation (QSR), undergo rigorous pre-market approval processes, and maintain ongoing post-market surveillance to ensure their safety throughout their lifecycle.

For a pump manufacturer, a recall is a serious setback. Issues with quality control, adverse event reports, and post-market surveillance findings can all trigger recalls—and they are happening more frequently. Between January 2019 and May 2022, the US FDA recorded 145 recalls of infusion pumps.

This past May, a US-based company faced a Class 1 recall, the FDA's most serious, for its homecare infusion pumps due to various failures, including under-dosing. Thankfully, thorough post-market surveillance often catches issues early, allowing for proactive action through voluntary recalls. However, these recalls still result in significant costs for manufacturers and damage their reputations.

Importance of Accurate Flow Rate Testing

Accurate flow rate testing is necessary for preventing performance defects and costly recalls in infusion pumps. This testing involves evaluating the pump's performance across different flow rates, pressures, and delivery modes, focusing on key parameters like bolus dose (rapid, single-shot medication) and basal flow rate (consistent medication levels over time).

An analytical balance is essential in this process, providing precise and trustworthy measurements of the fluid volume dispensed. It helps verify that the pump accurately administers both bolus doses and continuous basal flow rates, reducing the risk of over- or under-dosing.

Environmental factors such as temperature, humidity, and pressure, along with issues like needle skimming of the test liquid and electrostatic charges, can affect measurement accuracy. Advanced lab weighing technologies that adapt to these conditions are crucial for maintaining the integrity of test results.

Choosing the Right Analytical Balance

For precise testing of insulin pumps, choosing the right lab balance is critical, particularly to comply with standards such as the IEC 60601-2-24 and AAMI TIR 101:2021, which provide testing guidelines. As a device manufacturer, you need to consider five essential parameters:

• Readability: This ranges from 1 mg in Precision Balances to 0.001 mg in Micro Balances. The TIR 101 provides guidance on selecting resolution values based on flow rates for optimal precision.
• Capacity: A high-capacity balance allows for high-quality readings over longer, uninterrupted testing periods, which is crucial for infusion and syringe pump testing.
• Linearity Accuracy: Maintaining accuracy across various weight values is vital as volume increases during testing.
• Drift Management: Fluctuations in weight readings can be minimized with a monolithic weighing system, which offers better stability than traditional multi-component systems.
• Data Integrity: Compliance with 21 CFR Part 11 and EU Annex 11 guarantees tamper-proof, timestamped electronic records.

The Cubis^® II series meets all these criteria and is an industry-recognized name in quality control applications. These premium balances excel in modern, regulated environments, offering exceptional performance, compliance support, and flexible connectivity.

Check out the video below for a short interview on this topic and find additional resources about infusion pump testing.