Plain English Summary
Background and study aims
The FreeStyle Libre sensor automatically measures blood glucose levels around the clock, and stores the data for later retrieval. The aim of this study is to assess the accuracy of this device compared with blood glucose strips for patients with type 1 and type 2 diabetes.
Who can participate?
Aged at least 18 with diabetes (type 1 or type 2).
What does the study involve?
All participants wear a masked FreeStyle Libre Flash Glucose Monitoring System for 14 days while going about their daily activities. That is, they wear the sensor according to labelling instructions but are not able to see any sensor glucose data, unless they choose to wear an optional second sensor (unmasked). The data collected is transferred and stored in the reader memory by regular scanning of the sensor by the participants. Participants also perform four fingerstick readings per day, using the built-in blood glucose test strip port in the device’s reader. These blood glucose strip results are visible to the patient throughout. During visit 1 to their trial participating clinic, each participant’s demographic data, height and weight is recorded and their HbA1c result obtained. Participants are then be trained on how to use the FreeStyle Libre Flash Glucose Monitoring System and instructed to scan the sensor with the reader immediately after they do a fingerstick test. Three to five days later a follow up phone call is made to check that participants have not had any issues. Participants return to the clinic on day 15 where their sensors are scanned prior to removal and the data uploaded. This is the end of their study participation. The data is subsequently analysed.
What are the possible benefits and risks of participating?
There may be no direct benefit to the participant by wearing the masked device. However, if the participant takes the option of wearing a second unmasked Sensor they can use this to manage their diabetes. Some participants may experience either mild or moderate symptoms associated with the sensor placement on the skin as this is attached by means of a medical grade adhesive. To minimize the risk of reactions, participants will be asked if they have a known allergy to medical grade adhesives prior to enrolment and checked at each visit.
Where is the study run from?
The Solent NHS Trust, Southampton, the Ipswich Hospital NHS Trust and the Oxford University Hospitals NHS Trust.
When is the study starting and how long is it expected to run for?
July 2015 to July 2025
Who is funding the study?
Abbott Diabetes Care Ltd (UK)
Who is the main contact?
Dr Pamela Reid
Masked performance check of the Abbott FreeStyle Libre Flash Glucose Monitoring System: an interventional trial
The aim of this study is to evaluate the accuracy and performance of the masked Abbott FreeStyle Libre Flash Glucose Monitoring System
NRES Committee North West - Lancaster, 20/03/2015, ref: 15/NW/0267
Multi-centre prospective single arm
Primary study design
Secondary study design
Patient information sheet
Not available in web format, please use contact details to request a participant information sheet
1. Participants will wear a Masked FreeStyle Libre Glucose Monitoring Sensor for 14 days, at the same time participants have an option to wear a second unmasked FreeStyle Libre Glucose Monitoring Sensor
2. Participants will also perform four fingerstick readings per day for each day of sensor wear using the built-in test strip port
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.
Secondary outcome measures
Precision within Sensor lot.
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Aged 18 years 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
12 participants per sensor lot, with up to three sensor lots tested per study event.
Participant exclusion criteria
1. Participated in the same study event
2. Be a member of the study 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
The primary device in the study is not being used in the same way as its on market intended use, (i.e. the sensor results are masked to the subject.) Therefore the findings from the study are of negligible value to the medical or scientific community and so it is challenging to publish. If the results highlight any interesting information we will consider specifically preparing a manuscript or abstract to report this.
Intention to publish date
Participant level data
Available on request
Results - basic reporting