1.
Blood Glucose Monitoring
(You Can’t Achieve Tight Control Without It)
Lecture 4
by Eric Holzman

2.
A Diabetic’s Guide to
Managing Diabetes
Without blood glucose testing, a diabetic is “blind”
• A normal person’s blood glucose
control system does not need external
adjustment because his body
– continuously monitors his blood glucose
level
– releases insulin or glucagon Type 1
– stores or releases glucose
• A diabetic’s blood glucose control
system requires external adjustment.
– Insulin and/or Medication
– Food
– Blood glucose testing to determine
what to do Type 2
• A diabetic who knows his blood glucose
level can decide whether he needs to
do nothing, take medication, exercise
or eat food.
9-18-07 by Eric Holzman 2

3.
A Diabetic’s Guide to
Managing Diabetes
Blood glucose level—
what does the number mean?
• Successful diabetes management aims for a normal blood glucose
level all day, every day.
Blood Glucose What it means What a diabetic
Level (mg/dL) should do
Below 60 Hypoglycemic (low Eat food with 5-10
blood glucose) grams fast acting
carbohydrate
60-80 Below normal Eat food with up to 5
grams carbohydrate
goal 80-100 Normal Do nothing
100-120 Above normal Exercise or take
insulin
Above 120 Hyperglycemic (high Take insulin
blood glucose)
9-18-07 by Eric Holzman 3

4.
A Diabetic’s Guide to
Managing Diabetes
Can you know what your blood glucose
level is without measuring it?
• If your blood glucose level is high (above 100 mg/dL), it’s doubtful that
you will be able to tell how high.
– I have no symptoms if I’m within or above my normal range (80-100 mg/dL).
• Hypoglycemia (60 mg/dL or lower) may be indicated by symptoms.
– Disorientation, lethargy, fatigued limbs, shakes, numbness, nausea
• Low blood glucose is a relative term: you may experience hypoglycemic
symptoms if your blood glucose level drops significantly below its “usual”
range.
– When I was diagnosed, my blood glucose level was 300-400 mg/dL.
– I implemented carb-reducing changes in my diet immediately.
– I experienced low blood glucose symptoms such as “shakes” as my blood
glucose fell from 300-400 to 200-300 mg/dL in a few days.
• Hypoglycemic unawareness is a major reason why testing is necessary
for insulin users.
– If my blood glucose level drops to 50 mg/dL several times over a period of a
few days, many symptoms go away—sometimes I feel almost normal.
9-18-07 by Eric Holzman 4

5.
A Diabetic’s Guide to
Managing Diabetes
How frequently should you measure
your blood glucose level?
• How often you should test depends on
– how stable your blood glucose level is throughout the day,
– Your ability to predict changes in your blood glucose level,
– the chance you might have a hypoglycemic reaction,
– how tight you want to control your blood glucose level.
• Tight control means more frequent testing.
– In a normal person, continuous monitoring is done by the pancreas.
– A diabetic on insulin tests
• before eating to determine how much insulin to take, and
• after eating to determine whether the dose was correct
6:30 AM 78 12:00 PM 77 6:00 PM 79 8:30 PM 97
Good day Breakfast 3.5 units Lunch 6 units Dinner 2.5 units snack 3 units
8/30/06 8:30 AM 102 2:00 PM 97 Bike for 22 minutes 10:30 PM 79
7:00 AM 94 12:30 PM 72 6:00 PM 77 9:00 PM 109
Bad day Breakfast 4 units Lunch 4.5 units Dinner 4.5 units snack 3.5 units
9/10/06 work outside 3:00 PM 63 8:00 PM 125 10:30 PM 113
9:00 AM 49
9-18-07 by Eric Holzman 5

6.
A Diabetic’s Guide to
Managing Diabetes
When do you test and why?
• Fasting—before eating
– A type 1 diabetic must know his blood glucose level to choose his insulin dose.
– Your fasting level tells you if your slow acting (basal) insulin dose requires adjustment.
• Post prandial—after eating provides important feedback
– Did you take the correct amount of medication?
– Did you eat too much?
– Did you over-exercise?
• Post prandial measurements should be made about two hours after eating.
– Your meals should be sized to digest in about two hours because
– fast acting insulin (Lispro and Aspart) operates for about two hours.
– If you overeat, 2:00 PM 71
• Digestion will take longer than two hours, and Lunch 5.5 units
• you may need to re-test after another hour. 4:30 PM 100
• Testing at bed-time is essential for insulin users. 6:00 PM 130
• You should test any time you think your blood glucose is too low.
9-18-07 by Eric Holzman 6

7.
A Diabetic’s Guide to
Managing Diabetes
Frequent testing enables you to
reduce your blood glucose level
• If you do not test after eating, your blood glucose level could remain high
until the next meal.
• Your bedtime test is the most important—your life may depend on it.
– Not testing at bedtime could mean disaster if your blood glucose level is low.
– A high blood glucose at bedtime means a whole night at the wrong level.
– Your bedtime and morning fasting tests give you essential feedback for
setting your long-acting insulin dose properly.
120 Snack
Blood glucose level
110
100
Testing more often
Dinner
means a lower average
90
Breakfast 7 tests/day
blood glucose level
80
4 tests/day
Lunch
70
6:00 AM 10:00 AM 2:00 PM 6:00 PM 10:00 PM
Time of day
9-18-07 by Eric Holzman 7

8.
A Diabetic’s Guide to
Managing Diabetes
Portable blood glucose measurement
equipment is essential for tight control
• A glucometer is a device that measures your blood glucose level.
• The test requires a spring-loaded lancing device and lancet to draw a
small drop of blood from your figure or arm.
• The blood sample is absorbed by a test strip, which is inserted the
glucometer.
9-18-07 by Eric Holzman 8

9.
A Diabetic’s Guide to
Managing Diabetes
How to choose a Glucometer—
Accuracy and precision matter the most
• Accuracy: correctness, degree of conformity of a measure to a standard or
true value.
• Precision: repeated measurements produce the same results.
• American Diabetes Association recommends accuracy goals to meter
manufacturers.
– < 10% for blood glucose levels between 30 mg/dL and 400 mg/dL
– Example: 90 mg/dL could really be anything from 81 mg/dL to 99 mg/dL
• A laboratory meter is the standard.
• Cardiovascular system carries blood throughout the body to feed our cells.
– Arteries carry blood from heart to smaller arteries, which carry blood to capillaries.
– Glucose and oxygen leave capillary blood to supply cells. Cells return waste.
– Capillaries deliver blood carrying waste to veins, which return blood to heart.
V. Peragallo-Dittko, “How Accurate is Your Meter,” Diabetes Self-Management, 9/10 2000.
9-18-07 by Eric Holzman 9

10.
A Diabetic’s Guide to
Managing Diabetes
How to choose a Glucometer—
why lab and glucometer tests may not agree
• Blood in capillaries has more glucose than that flowing in veins.
– After fasting, the difference is small.
– After eating, the difference is large.
• Laboratory samples are from veins, while glucometers measure glucose in
capillary blood.
– For closest comparison of lab and glucometer measurements, lab samples should
be taken during fasting periods.
• Laboratories measure glucose level of plasma, the fluid in blood, while some
meters measure glucose level of whole blood (plasma and red blood cells).
– Measurements of whole blood are 10% to 15% lower than of plasma only.
• Most meters provide an average of 100 or more readings, which should
compare well with the result of an HbA1c test.
V. Peragallo-Dittko, “How Accurate is Your Meter,” Diabetes Self-Management, 9/10 2000.
9-18-07 by Eric Holzman 10

11.
A Diabetic’s Guide to
Managing Diabetes
How to choose a Glucometer—
other features that make your life easier
• Small blood sample—mine takes 2.5 microliters of blood.
• No coded entry for each new batch of strips reduces
chance of error.
• Quick analysis time: 15 seconds or less.
• Storage of 100+ readings and calculation of long term
averages.
– Averages tend to be very accurate—should compare with
HbA1c. This is a small
– Take an even mix of pre and post-prandial readings. sample: a few
microliters
• Too many fasting readings may bias the average to the low side.
• Too many post-prandial readings may bias it high.
• January Issue of Diabetes Forecast Magazine lists latest
equipment from all manufacturers.
9-18-07 by Eric Holzman 11

12.
A Diabetic’s Guide to
Managing Diabetes
How to choose a glucometer—
the most overrated feature
• Some glucometers can transfer stored
results to a computer.
• By themselves, the readings don’t tell
you that much.
– Many things determine your blood
glucose level at any one time: time of
day, activity level, medication dosage,
when, what & how much you last ate,…
– Unless you transfer all these additional
data to your PC, plotting blood glucose
readings by themselves will not be
useful.
• Your test results should be kept as part
of a written record containing your food Use this
intake, medication dosage and level of instead of
physical activity.
this
• I write all my data in small book, with 7
days of records viewable at a glance,
so I can see the trends.
9-18-07 by Eric Holzman 12

13.
A Diabetic’s Guide to
Managing Diabetes
Testing--a small amount of preparation
means accuracy and consistency
• Wash your hands with soap prior to testing.
– I always wash my hands in the bathroom.
– Not near a washroom? Carry some small towlettes with you.
• Dry your hands with a clean towel or a paper towel—not a kitchen
towel, which might have food residue on it.
• It is easiest to get a blood sample from warm hands.
– If your hands are cold, shake your fingers towards the floor to get the blood
flowing to your fingertips.
9-18-07 Bernstein, pp. 69-72 by Eric Holzman 13

14.
A Diabetic’s Guide to
Managing Diabetes
Measuring your blood glucose level is
quick, easy and almost painless
• Lance your finger • Try to apply the • Often, you must
from the side for blood sample to the insert the strip into
minimum pain. strip as quickly as the meter before
possible without applying the blood
• You may need to rushing. sample to the strip.
squeeze your
• If the sample is too
finger to get a small (it does not fill
large enough blood the strip), ignore the
sample. reading, and start
again with a new
• Switch fingers for
strip.
your next test.
9-18-07 by Eric Holzman 14

15.
A Diabetic’s Guide to
Managing Diabetes
You should question your glucometer’s
result if it is not what you expect
• Even a glucometer that works perfectly can
give an inaccurate reading.
– Some meters require a code for each batch of
strips—make sure the correct code is in use.
• A false high reading can cause you to take
medication and lead to a hypoglycemic
reaction.
• What should you do? Test a 2nd time from a
different site.
– If the 2nd reading differs greatly from the 1st
(>10 points difference), wash your hands and
test a 3rd time.
– Usually, 2 of the 3 readings will be in close
agreement. Average the closest two readings.
9-18-07 by Eric Holzman 15

16.
A Diabetic’s Guide to
Managing Diabetes
Sore Fingers--what about other test sites?
• Other test sites generally do not give real-time results like fingers (see
Roche glucometer manual).
• Evaluate a new site by comparing it with a result from a finger stick
taken at the same time.
– Take two readings, one from your finger and one from the new site.
– If the difference is greater than 5 points, retake both readings.
– You want to see a majority of readings at each site in close agreement.
• For example, you want to test from your arm instead of your fingers.
– Since the two readings at each site are close, you can conclude, that the
roughly 20 point difference is due to the site choice.
TEST 1 TEST 2
90 87
110 105
9-18-07 by Eric Holzman 16

17.
A Diabetic’s Guide to
Managing Diabetes
The A1C test: a diabetic’s report card
• The glycosylated hemoglobin (HbA1c) test gives an indication of “average” blood
glucose control over previous 2-3 months.
– fasting not required
• Red blood cells allow glucose to freely enter and leave without aid of insulin.
– Concentration of glucose inside a red blood cell is the same as that in the blood.
• Hemoglobin: a molecule found in red blood cells.
– Carries oxygen from lungs to body’s cells.
– Variety of types; HbA1c is the type that interests diabetics.
– HbA1c joins with glucose (is glycosylated) for the life of the blood cell, about 4 months.
• This test measures the % of hemoglobin HbA1c molecules that are glycosylated.
• Since your blood contains a mix of blood cells of different ages, blood cells aged
0-4 months contribute to the test result.
– 50% determined by blood glucose levels in the month before the test.
• Take an A1C test at least twice a year.
• Result is a percentage—5% is normal: 1 out of 20 hemoglobin are glycosylated.
M. Nakamoto, “H-B-A-1-C (what it is and why it matters),” Diabetes Self-Management, Jan/Feb 2004, pp. 84-89.
9-18-07 by Eric Holzman 17

18.
A Diabetic’s Guide to
Managing Diabetes
Relating A1C test results to
your glucometer readings
• Two weeks of carefully taken glucometer readings (80-100 readings),
half pre- and half post-prandial, can be an indicator of your long-term
blood glucose level.
• The HbA1c test, taken by your doctor, provides an independent
confirmation of how you are doing.
A1C Plasma Glucose Whole Blood Glucose
result (%) level (mg/dL) level (mg/dL)
5 100 90
5.4%, my average
6 135 121
7%, ADA recommended 7 170 152
maximum 8 205 183
9 240 214
9-10%, diabetic average
10 275 246
11 310 277
12 345 308
12.2%, my level at diagnosis
9-18-07 by Eric Holzman 18

19.
A Diabetic’s Guide to
Managing Diabetes
How Accurate is the A1C test?
• My experience: two tests at two different labs taken 10 days apart:
6.2%, 5.3%
• There are more than 30 different methods to measure A1C.
• Different brands of instruments using the same method can give
different results.
• All hemoglobin are not created the same.
• Go to the same lab so that you can compare your results and track
changes over time.
• Finger-stick HbA1c meters are as accurate as laboratory meters that
use blood from veins.
9-18-07 by Eric Holzman 19

20.
A Diabetic’s Guide to
Managing Diabetes
The DCCT tells us to
aim for normal blood glucose
• DCCT: Diabetes Control and Complication Trial
– a ten-year study of 1441 Type 1 diabetics
– to evaluate the effects of improved control of blood glucose
– diabetics split between intensive and conventional therapy
– Intensive group averaged 7% HbA1c; conventional averaged 9% HbA1c
• The reduction in complications was huge in patients with near normal control
– test was stopped early so the results could be made available to all
– reduction in HbA1c corresponded to proportional reduction in risk of complications
– risk of complications drops to zero for normal glucose levels
– Intensive group had 3x higher risk of severe hypoglycemia (BG< 50 mg/dL)
• Any reduction in HbA1c means reduced risk of complications.
– 10% reduction: 30-40% reduced risk of retinopathy (eyes), nephropathy (kidneys),
neuropathy (nerves)
– Dropping from a 9% to a 6% HbA1c means a 75% drop in risk of complications.
9-18-07 Bernstein, pp. 37-38 by Eric Holzman 20

21.
A Diabetic’s Guide to
Managing Diabetes
HbA1c test—normal should be your goal
• The average diabetic’s HbA1c test result is 9%.
– Equivalent to greater than 200 mg/dL all the time.
– Twice as much blood glucose as a normal person.
• The ADA’s recommends 7%, but you should do better.
– 7% is not normal.
– Complications will develop slowly.
• A Normal HbA1c—4.8% to 5.8%—should be your goal.
• With today’s glucometers, dieting, exercise and medication, normal is
achievable.
9-18-07 by Eric Holzman 21

22.
A Diabetic’s Guide to
Managing Diabetes
Do short term, high blood glucose
readings affect your health?
• Because fast-acting insulin does not reduce blood glucose as fast as a
normal pancreas, post-prandial spikes in blood glucose can occur.
• Bernstein says that damage done by high blood glucose can be stopped or
reversed by returning blood glucose to normal levels.
• How quickly you catch and reduce a high blood glucose level is what matters.
– Frequent testing enables you to spot high glucose levels soon after they occur.
– You reduce your blood glucose level quickly with insulin and/or exercise.
• Short-term spikes in glucose may not influence HbA1c results.
– Glucose takes time to join with blood cell hemoglobin
– Unless blood cells are joined with glucose, they won’t affect your HbA1c.
– However, glucose not joined to hemoglobin is still carried in your blood, and may
cause damage to your body.
• My experience—despite my “normal” HbA1c tests and near normal blood
glucose control, I developed low level retinopathy in my left eye 7 years after
diagnosis.
9-18-07 by Eric Holzman 22

23.
A Diabetic’s Guide to
Managing Diabetes
Short term spikes in blood glucose level can
occur when you are most insulin resistant
• Spikes in blood glucose level occur when we are most insulin resistant, which
is in the morning for many people.
• 30 minutes after eating breakfast, my glucose level had climbed to 129.
• 1 hour after eating, my level was at 140.
• But 2 hours after eating, it was down to 97.
• A 50% reduction in my breakfast carb intake (to 10 grams) and 10 minutes of
exercise after eating reduced the spike from 40 points to just 10 points.
9-18-07 by Eric Holzman 23

24.
A Diabetic’s Guide to
Managing Diabetes
What should you know about
glucose testing to manage your diabetes?
• A diabetic who knows his blood glucose level can decide whether he
needs to do nothing, take medication, exercise or eat food.
• Successful diabetes management aims for a normal blood glucose
level all day, every day.
• Your bedtime test is the most important—your life may depend on it.
• Your blood test results should be kept as part of a written record
containing your food intake, medication dosage and level of physical
activity.
• The HbA1c test is a diabetic’s report card—it is a measure of “average”
blood glucose control over the last 2 to 3 months.
• Any reduction in HbA1c means a reduced risk of complications.
• A Normal HbA1c—4.8% to 5.8%—should be your goal.
9-18-07 by Eric Holzman 24

25.
A Diabetic’s Guide to
Managing Diabetes
Metric Units
• 28 grams (g) = 1 ounce
• 454 grams (g) = 1 pound
• 1 gram (g) = 1000 milligrams (mg)
• 1 liter (L) = 34 ounces
• 1 liter (L) = 10 deciliters (dL)
• Normal blood glucose level: 90 mg/dL
9-18-07 by Eric Holzman 25

26.
A Diabetic’s Guide to
Managing Diabetes
References
1. R. Bernstein, Dr. Bernstein’s Diabetes Solution, Little, Brown and
Company, 1997.
2. V. Peragallo-Dittko, “How Accurate is Your Meter,” Diabetes Self-
Management, 9/10 2000.
3. M. Nakamoto, “H-B-A-1-C (what it is and why it matters),” Diabetes
Self-Management, Jan/Feb 2004, pp. 84-89.
4. S. S. Roberts,”Are A1C Results Reliable,” Diabetes Forecast, March
2005, pp. 23-26.
5. “The Absence of a Glycemic Threshold for the Development of Long-
Term Complications: The Perspective of the Diabetes Control and
Complications Trial,” Diabetes, Vol. 45, October 1996, pp. 1289-1298.
6. Images from Google™ Image Search at http://images.google.com
9-18-07 by Eric Holzman 26