Hormone Health Network FreeStyle Libre User manual

For Safe and
Effective
Diabetes
Management

*The FreeStyle Libre reader
contains a blood glucose meter that
can be used for ngerstick readings.
Do ngersticks before making treatment
decisions when:
• The check blood glucose symbol appears
• You have symptoms that do not match
system readings
• You suspect the readings may not be accurate
• You have symptoms that may be due to high or
low blood glucose
• Your glucose is quickly rising or falling
(more than 2 mg/dL per minute)
FreeStyle Libre consists of
two parts: A sensor and a
touchscreen reader.
The disposable sensor
is worn on the back
of your upper arm. It
automatically monitors
your glucose throughout
the day and night. It is small (about the size
of 2 stacked quarters) and water-resistant for
swimming, bathing, and exercise. Each sensor
lasts up to 14 days (depending on the system)
before needing to be replaced. The sensor holds
a full 8-hour history of your glucose results.
The wireless, rechargeable reader is used to
painlessly scan the sensor. This can be done
quickly and discreetly, even through clothing. The
reader holds up to 90 days of glucose information.
With each scan, the reader screen shows your
current glucose reading, a graph showing the past
8 hours of your glucose history, and a trend arrow
showing whether your glucose is rising, falling, or
staying steady.
FreeStyle Libre is a system for continuous
glucose monitoring (CGM) that gives you easy
access to your glucose numbers. CGM has
been shown to help people keep blood glucose
in their target range and reduce episodes of
severe low blood sugar (hypoglycemia). This
can mean fewer health problems, day-to-day
and in the long run.
CGM: A Different Way to
Monitor Glucose
The most common way to check blood glucose levels is to
prick a nger to get a drop of blood (a ngerstick), then test
the blood with a blood glucose meter. The results are used to
make decisions about insulin, food, and exercise.
FreeStyle Libre systems use a sensor to test a thin layer
of uid between body cells. No blood sample is needed.
These “sensor glucose readings” are taken once a minute
and can be read with a simple swipe of a wireless reader.
Sensor glucose readings tend to be about 5 to 10 minutes
behind blood glucose readings. Even so, sensor glucose
readings can replace ngerstick readings for most treatment
decisions.*
How
FreeStyle
Libre
Works

*If the system cannot tell the direction of your glucose, it
will not show an arrow. Instead it will show the check blood
glucose symbol:
If that symbol appears, check your blood glucose
and use the result to make any needed treatment
decisions.
Note: When you rst start using the
FreeStyle Libre system, use only blood
glucose readings to make treatment
decisions. Scan often to get a sense
of how food, medication, exercise,
and other factors affect your sensor
glucose readings. When you have
a good understanding of how
the system works for your body,
you can start using sensor
glucose readings for treatment
decisions.
After each scan, the Sensor
Glucose Readings screen appears.
The screen shows your current
glucose reading, a graph of your
past 8 hours of glucose history,
and a glucose trend arrow.
Understanding Trend
Arrows
What the
Trend Arrow
Tells You
The trend arrow tells you
how quickly or slowly your
glucose is changing, and
in what direction.
There are 5 possible
arrow results .*
Glucose
rising
quickly
Glucose
rising
Glucose
changing
slowly
Glucose
falling
Glucose
falling
quickly
Because the trend arrows help show what direction
glucose is going, they can be used to help make
decisions about your treatment. Treatment decisions
based on trend arrows may include:
• Adjusting your insulin dose
• Eating a snack
• Using fast-acting carbohydrates
• Doing nothing and scanning to monitor changes
Using Trend Arrows to Help
Make Treatment Decisions

What to Know
This table is for adults who require insulin to manage
diabetes and who are taking rapid-acting insulin for
meals and corrections.
• Insulin adjustments using trend arrows do not
replace standard calculations using insulin-to-
carbohydrate ratio and correction factor. These
adjustments are increases or decreases of rapid-
acting insulin in addition to calculations using
insulin-to-carbohydrate ratio and correction factor.
• For quickly rising sensor glucose before a meal,
consider administering insulin 15 to 30 minutes
before eating.
• For quickly falling sensor glucose before a meal,
consider administering insulin closer to the meal.
• If quickly falling sensor glucose is close to or
lower than 150 mg/dL, consider not taking your
pre-meal insulin dose until glucose has stabilized.
• If you are of older age or are in poor health,
you may be given revised instructions to help
better reduce your risk for low blood sugar
(hypoglycemia). If this might apply to you, talk with
your healthcare provider.
• When rounding of the insulin dose is needed:
Insulin Dose Adjustments Using the FreeStyle Libre System Trend Arrows in Adults:
Pre-Meal and Corrections 4 or More Hours Post-Meal
Insulin Dose Adjustments
FreeStyle
Libre Trend
Arrows
Correction Factor (CF)*
Less than 25
(<25) 25 to less than 50 (25 to <50) 50 to less than 75 (50 to <75) 75 or higher (≥75)
+3.5 units +2.5 units +1.5 units +1.0 units
+2.5 units +1.5 units +1.0 units +0.5 units
No adjustment No adjustment No adjustment No adjustment
-2.5 units -1.5 units -1.0 units -0.5 units
-3.5 units -2.5 units -1.5 units -1.0 units
*Correction factor (CF) is in mg/dL and indicates glucose lowering per unit of rapid-acting insulin.
Adjusting Insulin Dose
for Adults Using
Trend Arrows:
Before Meals and
4+ Hours After Meals
Mealtime is ideal to begin applying insulin
dose adjustments using trend arrows. The
following table gives you information on using
trend arrows to help adjust your insulin dose
before and several hours after meals.
Your insulin dose is based on your food, your correction factor,
and your trend arrow adjustment. Adjusting your dose using the
trend arrows does not replace your standard care plan, including
carb counting and related adjustments. Be sure to follow the
treatment plan you and your healthcare provider have outlined.
||Calculate total insulin dose using usual
parameters.
||Round to the nearest whole number or
half unit, as appropriate.
||If at a midpoint (for example, 0.5 units)
and you need to round to a whole number:
~|
Round up when a level or upward arrow
is present.
~|
Round down when a downward arrow
is present.

Avoid Insulin Stacking
If your most recent scan shows that your glucose
is high and still rising, you may be tempted
to take more insulin to lower it.
However, if you’ve recently taken a
bolus of insulin, taking another
too soon (insulin stacking)
can result in low blood
sugar (hypoglycemia). The
right treatment for high and
rising glucose depends on
several factors, including
when you last took insulin
and your recent activity. The
best decision may be to do
nothing right now and scan
again a bit later.
Special
Considerations
When Using CGM
If You’re Sick
Illness can make it hard to keep your blood
sugar in your target range. Your blood sugar can
rise quickly when you’re sick. Keep these
recommendations in mind for using
CGM on sick days:
• Scan more often.
• In addition to scanning,
do a ngerstick and
check your blood
glucose every
2 to 4 hours.
• Monitor ketones
as you have been
instructed.
Be sure to talk with your
diabetes healthcare team
and develop an action plan for
sick days. This includes how to
adjust your meal plan and insulin.
Aspirin and Vitamin C
Taking 650 mg or more of aspirin (or any pain
reliever containing salicylic acid) can affect
sensor glucose levels. So can 500 mg or more of
vitamin C. If you take this much or more of either
substance, check your blood glucose in addition
to scanning.
Exercise
Being active is good for your health, but it
does affect your blood glucose level. Plan
ahead as much as possible to help avoid
low blood sugar (hypoglycemia). It is often
a good idea to avoid exercise until 2 hours
after taking a bolus dose of insulin. This will
help keep glucose from changing quickly.
Delayed low blood sugar sometimes occurs
about 6 to 8 hours after exercise. Watch
for this by scanning more often. Work with
your healthcare team to develop a plan for
managing glucose during very intense exercise
or exercise lasting longer than 2½ hours.
<100 mg/dL 100 – 180
mg/dL 181 – 250 mg/dL >250 mg/dL
DO NOT
Exercise
Ingest
carbohydrate
and/or wait
until >100 mg/dL
Carefully
Exercise
Re-scan every 30
minutes to avoid
low blood sugar
Exercise
Away
Re-scan every 30
minutes to avoid
low blood sugar
DO NOT
Exercise
Correct and/or
wait until
≤250 mg/dL
Wait until
> 100 mg/dL
Rescan in 30 min Rescan in 30 min Correct to
≤180 mg/dL
Wait until
> 100 mg/dL
Rescan in 30 min Rescan in 30 min Correct to
≤180 mg/dL
Ingest 15 g
carbohydrate
Consider
ingesting 15 g
carbohydrate
Rescan in 30 min Correct to
≤180 mg/dL
Ingest 15 g
carbohydrate
Consider
ingesting 15 g
carbohydrate
Rescan in 30 min Wait until
≤250 mg/dL
Ingest 30 g
carbohydrate
Consider
ingesting 30 g
carbohydrate
Consider
ingesting 15 g
carbohydrate
Wait until
≤250 mg/dL

Questions for Your Healthcare
Team About CGM
• Is CGM right for me?
• Does CGM t into my diabetes management plan?
• Would CGM help me better manage my diabetes?
• What adjustments would we need to make to my diabetes
management plan to use CGM?
• What is my target blood glucose?
• How often should I scan?
• How do I share my sensor data with you?
• Is CGM covered by my insurance plan?
How Often
to Scan
Scanning with the FreeStyle Libre system is
easy and quick. Because of this, you might
be tempted to scan more often than you
need to. You may then feel overwhelmed
by data. On the other hand, scanning only
a few times a day may cause you to miss
important information. This page gives
general recommendations for how often
to scan. Certain factors and situations may
mean you need to scan more often.
When to Scan Why?
Mornings after
waking up
Gives you an overview of your glucose
trends overnight. Allows you to make
adjustments to stay in target range.
Just before a
meal
Gives you information for making calcu-
lations of insulin dose and timing.
Two hours after
a meal
Gives you an overview of the glucose
changes after your meal. Allows you to
take action to correct glucose, if needed.
Before going
to bed
Gives you current sensor glucose and
trend arrow information. Lets you take
action to help prevent blood sugar going
too low or too high during the night.
Other Scanning Recommendations
• On sick days: Scan every 2 hours.
• For exercise: Scan before exercise and every 15 to
30 minutes during exercise. Scan right after stopping
exercise and again 6 to 8 hours later.
• If you have taken action to treat an episode of high
blood sugar (hyperglycemia): Scan at least once every
hour for the next 4 hours. Check that glucose goes back
to target range and doesn’t go too low.
• If you have taken action to treat an episode of low
blood sugar (hypoglycemia): Scan every 15 minutes until
your glucose is steady within your target range. Follow
your treatment plan regarding when to take more action if
your glucose continues to stay low.
• When the trend arrow is at and sensor glucose is close
to the low end of your target range, scan more often for a
time to help avoid low blood sugar.
Scan at least every 8 hours. This prevents a gap in glucose
data, since the sensor only holds 8 hours of information.
EDITORS:
Leonor Corsino, MD, FACE, MHS
Ramon Martinez, MD
Davida Kruger, MSN, APN-BC, BC-ADM
Eden Miller, DO
L. Kurt Midyett, MD
You have questions. We have answers.
The Hormone Health Network is your trusted
source for endocrine patient education.
Developed for patients based on Approach to Using
Trend Arrows in the FreeStyle Libre Flash Glucose
Monitoring Systems in Adults, an Endocrine
Society Publication. #js.2018-00294R1
www.hormone.org