Plain English Summary
Background and study aims
The FreeStyle Libre Flash Glucose Monitoring System is a new system for measuring glucose levels and is CE marked and marketed within the UK. The aim of this study is to evaluate the accuracy of the system for people with diabetes, especially those who take insulin.
Who can participate?
Adults aged 18 and over who have type 1 or 2 diabetes.
What does the study involve?
Participants will wear the Sensor according to labelling instructions. The data is transferred and stored in the Reader memory by regular scanning of the Sensor by the participants. Each study event will aim to recruit 36 participants across approximately three UK sites. Once a study event is complete another one will commence, on a continuing basis. Each participant will be in the study for up to fifteen days. Participants will wear a FreeStyle Libre Flash Glucose Monitoring System for 14 days while going about their daily activities. Participants will perform four BG fingerstick readings per day for each day of Sensor wear using the built-in test strip port in the Reader to allow evaluation of Sensor accuracy. During Visit 1 participants will provide demographic data, their height and weight will be recorded. Participants will be trained on how to use the FreeStyle Libre Flash Glucose Monitoring System. They will also be instructed to scan the Sensor with the Reader immediately after they do a fingerstick test. Participants will return to the clinic on day 15 where their Sensors will be scanned prior to removal and the data uploaded. This is the end of their study participation. The data will subsequently be analysed at Abbott Diabetes Care.
What are the possible benefits and risks of participating?
This study gives participants the opportunity to use flash glucose monitoring as a way of managing their diabetes, which may be of benefit.
There are risks associated with the use of any device that punctures the skin. FreeStyle Libre Flash Glucose Monitoring System uses a delivery applicator that places the Sensor ½ cm (or 1/5 inch) into the skin. The participant may experience some mild or moderate symptoms associated with the Sensor insertion or the adhesive used to keep the Sensor in place. These include redness, swelling, rash, itching, bruising, pain and bleeding. Blood glucose testing on the Reader may require a few drops (less than 1/100 teaspoon) of blood per day. The risks are the same as the participants' current blood glucose testing. It may hurt when the lancet goes into the skin; this could produce bruising and a small scar, which could last for several weeks plus there is a low risk of infection. There are similar small risks with the collection of a blood sample for the HbA1c blood test, plus possible dizziness. The amount of blood taken for this test (if one is required) will be up to about 1-2 teaspoons.
Where is the study run from?
Three hospitals in the UK: Oxford Centre for Diabetes, Endocrinology and metabolism (OCDEM), Oxford, The Ipswich Hospital, Ipswich, and Royal South Hants Hospital, Southampton.
When is the study starting and how long is it expected to run for?
From January 2015 to December 2024.
Who is funding the study?
Abbott Diabetes Care Ltd (UK).
Who is the main contact?
Dr Pamela Reid
ADC-UK-PMS-14020, IRAS Project ID: 161804
Performance Check of the Abbott FreeStyle Libre Flash Glucose Monitoring System: a multi-centre prospective open single arm study
The study is to evaluate the accuracy of the Abbott FreeStyle Libre Flash Glucose Monitoring System, designed for testing of blood glucose for people with diabetes, especially those who take insulin.
NRES Committee West Midlands - South Birmingham, 17/11/2014, REC Reference: 14/WM/1136
Multi-centre (3 UK sites) prospective open single arm
Primary study design
Secondary study design
Non randomised study
Patient information sheet
Participants will wear a FreeStyle Libre Flash Glucose Monitoring System for 14 days.
Participants will also perform four fingerstick readings per day for each day of Sensor wear using the built-in test strip.
Primary outcome measures
Accuracy performance of the Abbott FreeStyle Libre Flash Glucose Monitoring System compared to capillary fingerstick blood glucose values (FreeStyle Optium blood glucose test strips) using the consensus error grid. For all primary and secondary outcomes, the data is generated during the Sensor wear period (up to 14 days) during which the participant measures their blood glucose (BG) at least 4 times a day with corresponding Sensor scans. The data recorded in the Reader will be uploaded at visit 2 (day 15) and subsequently transferred to Abbott Diabetes Care (ADC) for analysis. The primary outcome will be measured by calculating the proportion of paired Sensor and BG values within each zone of the Consensus Error Grid.
Secondary outcome measures
1. Precision within Sensor lot estimated by calculating the coefficient of variation of Sensor slopes. Slopes will be calculated for each sensor by standard linear regression of Sensor Glucose vs. BG.
2. Relationship between HbA1c levels and glycaemic variability, determined from Sensor glucose values.
For all primary and secondary outcomes, the data is generated during the Sensor wear period (up to 14 days) during which the participant measures their blood glucose (BG) at least 4 times a day with corresponding Sensor scans. The data recorded in the Reader will be uploaded at visit 2 (day 15) and subsequently transferred to Abbott Diabetes Care (ADC) for analysis.
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Aged 18 or over
2. Have type 1 or type 2 diabetes
3. Be self-testing their blood glucose levels at least twice per day
4. Be able to follow the instructions provided to him/her by the study site and perform all study tasks as specified by the protocol, in the investigator’s opinion
5. Be available for all study visits
6. Be willing to provide written informed consent
Target number of participants
Each study event will aim to recruit 36 participants (30 minimum). Ten study events can occur per year, therefore, a total of up to 360 participants will be recruited per year, with the protocol end date in December 2024, there will be up to 3600 participants recruited in this study protocol.
Participant exclusion criteria
1. Participated in the same study event
2. Be a member of the site staff
3. Have a known allergy to medical grade adhesive
4. Be pregnant or planning to become pregnant within the study event duration
5. Have skin abnormality at the application sites
6. Have a pacemaker or any other neuro stimulators
7. Have concomitant medical condition which in the investigator’s opinion could interfere with the study or present a risk to the safety or welfare of the participant or study staff
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Solent NHS Trust
Trial participating centre
The Ipswich Hospital NHS Trust
Trial participating centre
Oxford University Hospitals NHS Trust
Abbott Diabetes Care Ltd
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Following study completion, results are expected to be submitted for publication. The purpose of this study is to monitor the ongoing analytical performance of the FreeStyle Libre Flash Glucose Monitoring System as part of a post-market surveillance program and therefore would be published as such in accordance with the primary/secondary endpoints described.
Intention to publish date
Participant level data
Available on request
Results - basic reporting