FAQ's

What is the FreeStyle Navigator System?

Learn more about the FreeStyle Navigator Continuous Glucose Monitoring System.

1. What is the FreeStyle Navigator Continuous Glucose Monitoring System?

   The FreeStyle Navigator Continuous Glucose Monitoring System is a glucose monitoring device that continuously measures, displays, and records the glucose levels in the fluid found between the cells under the skin (interstitial fluid). It provides a glucose reading once every minute. It does this by using a small, thin, plastic sensor that is inserted about 5 mm under the skin. A transmitter that is attached to the sensor sends the glucose data through wireless communication to a compact handheld display unit called the receiver.

2. How is continuous glucose monitoring different from traditional blood glucose monitoring?

   Traditional blood glucose testing provides patients with glucose readings that represent distinct points in time. Patients do not get comprehensive information regarding how their glucose levels have been changing, nor do they get information about where their glucose levels are heading. Without such information it can be easy to miss significant glucose fluctuations - the ups and downs.

   Continuous glucose monitoring gives a more complete picture of glucose fluctuations by providing glucose values each minute. Understanding how their glucose levels have been changing makes it possible for patients and their healthcare team to take appropriate actions and make therapy adjustments. Furthermore, with the FreeStyle Navigator system, users can now know in advance about glucose highs and lows and take action to reduce and hopefully prevent severe glucose fluctuations.

3. How does the FreeStyle Navigator system work? What are its components?

   The FreeStyle Navigator system contains three main components

   • A disposable sensor that is inserted under the skin. The sensor can be applied to the back of the upper arm or the abdomen and can be worn on the body continuously for up to 5 days. The sensor is inserted under the skin and adhered to the skin with an adhesive. It measures glucose continuously in the interstitial fluid. Only a small (5 mm long) microfilament is inserted under the skin.
   • A reusable wireless transmitter that attaches to the sensor and sends the glucose readings to the receiver anywhere within a 3 metre range. The transmitter is suitable for everyday activities including exercise, bathing, and swimming.
   • A compact handheld receiver that receives the glucose readings from the transmitter and displays them on the screen. The receiver also contains a built-in FreeStyle® blood glucose meter for convenient calibration and blood glucose measurements.

   In order to measure glucose levels continuously, the sensor is placed under the skin. Each FreeStyle Navigator sensor comes in a sterile package called the Sensor Delivery Unit. This unit contains a spring-loaded insertion device that places the sensor under the skin. The sensor delivery unit is automatic and disposable. The user simply presses a button to insert the sensor, after which the sensor delivery unit is thrown away. The sensor is held in place by a plastic support mount.

   As the user slides the transmitter onto the support mount, the transmitter snaps into place on the sensor support mount and makes contact with the sensor. The support mount is held on the skin by an adhesive. The transmitter sends glucose readings wirelessly from the sensor to the handheld receiver once every minute. The receiver then displays the glucose readings and other information. The sensor can be worn for up to 5 days. After the 5 days, the old sensor is removed and a new one inserted. Each transmitter and receiver pair is designed to work with only one sensor at a time. Users will not be able to wear two sensors simultaneously using a single system.

4. Why should I prescribe the FreeStyle Navigator Continuous Glucose Monitoring System?

   The FreeStyle Navigator system provides customizable early-warning alarms approximately 10, 20 or 30 minutes in advance of glucose highs and lows. This means that users can take action before reaching a potentially dangerous low or high glucose condition.

   For patients, knowing that their glucose level is currently 5.6 mmol/L but that it will be 3.3 mmol/L in 20 minutes can help them decide whether to drive, do strenuous exercise, eat before a meeting, and the like, and consequently reduce the worry that often accompanies life with diabetes.

   The FreeStyle Navigator sensor uses exclusive Wired Enzyme technology that enables the system to measure glucose very accurately. This unique technology provides users with stable, reliable glucose readings.

   The FreeStyle Navigator sensor can be worn for up to 5 days.

   The system is entirely wireless for added convenience. There are no wires or cables. Users will get continuous glucose readings once every minute as long as the receiver is within 3 metres of the transmitter.

   The system uses batteries that can be changed easily without having to replace the entire device.

   The sensor insertion process is simple and automatic. Users can insert the sensor by pressing a button on the sensor delivery unit and then simply throw it away. Users don't see the needle or the sensor. Simple and Safe!

   Only the FreeStyle Navigator system includes a built-in blood glucose meter for convenient calibration and blood glucose measurements. With the world's smallest blood sample size, the FreeStyle meter's patented technology offers its own distinct set of advantages.

   Additionally, the FreeStyle Navigator sensors need not be refrigerated. The transmitter can be submerged in water for 30 minutes up to a depth 1 metre making it suitable for everyday activities including bathing, exercise, and swimming.

5. What is a TRU™ Directional Arrow?

   The FreeStyle Navigator system provides TRU™ Directional Arrows with each glucose reading that tell users which way and how quickly glucose levels are changing. So, at any given time, they not only know what their glucose level is currently, but also which way it is heading. There are a total of five arrows that tell users whether your glucose levels are changing gradually, moderately, or rapidly.

6. How far can the receiver be from the transmitter without missing glucose readings?

   The receiver can receive and display glucose readings anywhere within a 3 metre range of the transmitter. When the connection is lost, the receiver beeps and lets the user know that the connection is broken.

   If the connection is lost, glucose readings will not be displayed. Once the receiver is within 3 metres of the transmitter, glucose readings will start again automatically.

7. Where can the sensor be worn?

   The sensor can be worn on the back of the upper arm or the abdomen. Studies show that there is no difference in the performance and accuracy of the system between the arm and abdomen. The insertion site can be rotated from arm to abdomen.

8. How big is the sensor? How deeply does it get inserted?

   The sensor is about the size of a penny and is made from a plastic material. The portion of the sensor that gets inserted under the skin is less than a millimeter wide (1 mm is about the thickness of a few strands of human hair) and it is inserted only about 5 mm under the skin. Studies indicate that a vast majority (80.2%) of users found the insertion no more painful than a finger-stick test.1

9. Can the sensor be inserted in other sites on the body?

   Abbott Diabetes Care has performed studies that demonstrate that the sensor can safely be inserted on the back of the upper arm and the abdomen. Research studies are not yet available to validate that the glucose results from a sensor inserted into other sites of the body would be the same as the glucose results from a sensor inserted in the approved sites (back of the upper arm and abdomen).

10. Does the FreeStyle Navigator system require calibration?

    Yes. The system needs to be calibrated to finger-stick blood glucose measurements. The system contains a built-in FreeStyle blood glucose meter for convenient calibration and blood glucose measurements. The system requires four calibrations during a 5-day wear period. The calibrations are at approximately 1, 2, 10, 24 and 72 hours after sensor insertion. Additional calibrations may be necessary, when glucose is changing rapidly. There will be no continuous glucose readings until the first calibration is completed successfully. When the conditions are not conducive, the system automatically prevents calibration so that it can maintain glucose measurement accuracy.

11. What is calibration?

    Calibration allows the system to match the glucose readings from the sensor with a standard reference. In the case of the FreeStyle Navigator system, the reference is the finger-stick blood glucose measurement taken with the built-in blood glucose meter. The system requires calibration on a periodic basis so that the continuous glucose results from the sensor accurately reflect the capillary blood glucose readings.

    Through our clinical studies and research, we have determined that calibrating the system a minimum of 5 times (over the 5-day wear period) is sufficient to provide accurate results. In fact, a typical calibration schedule does not require any calibration on the last two days of the up to 5-day wear. This is made possible by the sensor's unique Wired Enzyme technology that provides a stable glucose signal.

    Calibration of the system establishes how sensor data are converted to a glucose value. It is therefore important to follow the correct testing techniques when performing a blood glucose test for calibration. Users can ensure proper testing technique by making sure their fingers are clean and dry, by using the correct test strip code, and by using ONLY blood from the fingertips for calibration.

    Note: When your glucose levels are changing rapidly, the difference between glucose levels in capillary blood and interstitial fluid can be magnified. Therefore, it is important to remember to calibrate when your glucose levels are relatively stable. Users can do this in most cases by avoiding calibration during or right after meals, exercise, or insulin dosing.

12. How do users know if their glucose level is changing?

    The FreeStyle Navigator system's TRU™ Directional Arrows show which way and how quickly glucose levels are changing. When glucose levels are changing rapidly, the arrow points straight up or straight down. In addition, there are also built-in algorithms that detect rapid changes in glucose levels and delay the request for calibration automatically.

13. Why does it take 1 hour to do the first calibration?

    Abbott Diabetes Care is committed to making its products safe for the user. Soon after the insertion of a sensor, there are physiological processes that happen as the sensor and the body equilibrate. These processes are part of the body's natural response to a foreign object. The equilibration process can vary from one person to another and may not always happen in the same manner for any one person. We have found through our research and studies that it is not always easy to accurately measure glucose in the body when this equilibration happens. Therefore, we have decided to let the system equilibrate for 1 hour in order to ensure that the system is providing accurate glucose readings. Of course, we recognize the importance of providing more immediate glucose information and we are actively pursuing ways to reduce the time required to do the first calibration without compromising the system's accuracy.

14. Do users have to carry a separate blood glucose meter?

    No. The FreeStyle Navigator system contains a built-in FreeStyle blood glucose meter for convenient calibration and blood glucose measurements. Fewer things to carry around!

15. Is the FreeStyle Navigator transmitter water-resistant?

    Yes! The transmitter that is worn on the body is water-resistant in up to 1 metre of water for 30 minutes. The system is suitable for everyday activities including exercise, bathing, and swimming. The receiver, which contains a test strip port, should not be immersed in water or any other liquid. Water or any other liquid should not be allowed to enter the test strip port.

16. What kind of batteries does the system use?

    The system uses replaceable batteries. The transmitter uses one 357 HC type battery that lasts approximately 30 days. A 357 HC type battery is provided with every sensor kit (containing a month's supply of sensors). The receiver uses two AAA type batteries that last approximately 60 days. Energizer® alkaline batteries are recommended.

17. What about alarms?

    The FreeStyle Navigator system provides many safety alarms. There are alarms for low and high glucose conditions. You can set the glucose levels for your alarms between 3.3 mmol/L and 16.7 mmol/L. The FreeStyle Navigator system has early-warning alarms that alert approximately 10, 20, or 30 minutes in advance glucose highs and lows. In addition, there are alarms for low battery conditions, calibration prompts, sensor replacement, and other system functions. All these alarms can be set to three different levels of volume - in beep or vibrate modes or they can be turned off entirely, if desired.

18. What is Interstitial Fluid (ISF) and how is it different from blood?

    Interstitial fluid is the fluid in spaces between the cells in the body. Movement of nutrients, oxygen and glucose from the blood into the cells occurs across the blood vessel wall and interstitial fluid. Depending on how glucose is being consumed by surrounding cells and how rapidly the glucose is changing, there may be some differences between the glucose levels in capillary blood (which traditional blood glucose meters measure) and interstitial fluid. When glucose levels are not changing rapidly, these differences are not significant enough to affect treatment decisions. However, these differences can be magnified during conditions of rapid changes in the blood glucose levels (for example, after eating, exercising or dosing insulin).

19. How accurate is the FreeStyle Navigator system? How does it compare with traditional blood glucose meters?

    The FreeStyle Navigator system has been proven to be clinically very accurate. In clinical studies, results from the FreeStyle Navigator system were compared to standard reference methods that are widely accepted by the industry and regulatory authorities. Performance evaluation of the FreeStyle Navigator system based on these established standards clearly demonstrates a high degree of accuracy.

    Traditional blood glucose meters provide glucose readings at the instant testing occurs. The FreeStyle Navigator system not only provides continuous readings once every minute but also shows which way and how quickly glucose levels are changing. Traditional methods of evaluating accuracy of glucose monitoring devices are not equipped to account for this rate and direction of glucose change. They are designed to compare point-in-time measurements alone. This makes it difficult to compare the accuracy of a traditional blood glucose meter and the FreeStyle Navigator system using the same techniques. However, data from the FreeStyle Navigator system clearly show that the readings are very accurate throughout the entire duration of its up to 5-day wear.

20. Is the FreeStyle Navigator system approved for use in children?

    The FreeStyle Navigator is licensed for use in children aged between 6 and 17 who are supervised by a caregiver who is at least 18 years of age.

    FreeStyle and Navigator are trademarks of the Abbott Group of companies in various jurisdictions.