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435
Self-Monitoring of Blood Glucose: Practical Aspects
Julienne K. Kirk, Pharm.D., C.D.E., and Jane Stegner, R.D., C.D.E.
Author Afliations: Department of Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina
Abbreviations: (ADA) American Diabetes Association, (CGMS) continuous glucose monitoring system, (DCCT) Diabetes Control
and Complications Trial, (A1C) hemoglobin A1c, (SMBG) self-monitoring of blood glucose, (T2DM) type 2 diabetes mellitus
Keywords: diabetes, glucose monitoring, lancing, self-monitoring of blood glucose
Corresponding Author: Julienne K. Kirk, Pharm.D., C.D.E., Department of Family and Community Medicine, Wake Forest University School
of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1084; email address jkirk@wfubmc.edu
Journal of Diabetes Science and Technology
Volume 4, Issue 2, March 2010
© Diabetes Technology Society
Abstract
Self-monitoring of blood glucose (SMBG) should be part of a regular management plan for patients with
diabetes. Self-monitoring of blood glucose provides information regarding an individual’s dynamic blood
glucose prole. This information can help with the appropriate scheduling of food, activity, and medication.
It is also required for understanding of the timing of blood glucose variations. Lack of regular SMBG predicts
hospitalization for diabetes-related complications. Self-monitoring of blood glucose is an essential tool
for people with diabetes who are taking insulin or for those who experience uctuations in their blood glucose
levels, especially hypoglycemia. Application of practical aspects that aid in easy management of SMBG makes the
task of checking blood glucose more achievable. For patients taking insulin and adjusting their dose, SMBG is
needed for self-management. For others receiving oral medication, proling glucose trends and the conrmation
of high or low blood glucose can be a useful addendum to successful management.
J Diabetes Sci Technol 2010;4(2):435-439
CLINICAL APPLICATIONS
Introduction
Self-monitoring of blood glucose (SMBG) can be a
useful tool in the management of diabetes mellitus.
Patients with diabetes often measure their blood glucose
to detect hypoglycemia and to adjust insulin dose as
needed. Others utilize SMBG to help establish a prole
of blood glucose levels and response to nutrition and
pharmacotherapy. The American Diabetes Association
(ADA) initially established guidelines for SMBG in 1987,
and current recommendations suggest regular SMBG in
persons with diabetes based on each patient’s needs.1,2
Records of SMBG can also be used during consultation
with diabetes health care providers to titrate blood glucose-
lowering agents and to guide physical activity and food
intake.
One objective of Healthy People 2010 is to increase the
number of adults with any type of diabetes who
perform SMBG at least once daily.3 Data from the
Behavioral Risk Factor Surveillance System, representing
25 of 38 states in the United States, reported this to
be 63.4% among all adults with diabetes and 86.7%
among those treated with insulin.4 For patients with
type 1 diabetes mellitus, it is recommended that patients
measure their blood glucose at least three times daily.2
The effectiveness of SMBG has been established for
insulin-treated patients.
There is debate over optimal frequency and timing of
SMBG for those with type 2 diabetes mellitus (T2DM)
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Self-Monitoring of Blood Glucose: Practical Aspects Kirk
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J Diabetes Sci Technol Vol 4, Issue 2, March 2010
not taking insulin. Some health practitioners are skeptical
about the effectiveness of SMBG as a self-management tool.
However, lack of regular SMBG predicts hospitalization
for diabetes-related complications.5 Self-monitoring of
blood glucose has also been shown to signicantly decrease
hemoglobin A1c (A1C).6,7 The ADA recommends using
SMBG as a guide to successful therapy and to achieve
postprandial glucose targets.2
Self-monitoring of blood glucose by persons with diabetes
is an integral part of intensive glycemic treatment and is
widely believed to improve the control of blood glucose
levels and health outcomes. The results of the Diabetes
Control and Complications Trial (DCCT) among persons
with type 1 diabetes mellitus showed that intensive
glycemic control signicantly slowed the progression of
diabetes complications.8 The DCCT protocol required
SMBG at least four times each day and multiple
injections of insulin. Furthermore, the United Kingdom
Prospective Diabetes Study found that a reduction in A1C
was associated with a decreased risk of microvascular
complications in persons with T2DM.9
Specic Goals of Blood Glucose and
Documentation
The target for A1C is less than 7%; this correlates with
an average blood glucose of approximately 150 mg/dl.
Specically, the ADA recommends that preprandial plasma
glucose values range from 70 to 130 mg/dl, and peak
postprandial levels are targeted at <180 mg/dl.2 The use
of SMBG by a person with diabetes can be helpful in
developing a longitudinal glucose prole and as an aid
in making day-to-day decisions. Standards of Medical Care
in Diabetes 2010 also recognizes that there is increased
risk for diabetes at a fasting plasma glucose of 100 to
125 mg/dl or a 2-hour postprandial glucose that is 140
to 199 mg/dl as well as a A1C level that is 5.7% to 6.4%.2
Furthermore, the new standards also recognize the use
of a A1C ≥6.5% as an option for diagnosis of diabetes if
the test is performed by a laboratory using a certied
methodology.2
It is advisable to have the patient record their SMBG values
in a log book. Information about food intake, medication,
and exercise can be important for interpreting the SMBG
results. Keeping a log will also encourage the patient
to acknowledge their SMBG and to contemplate the
potential adjustments they can make with activity and
nutrition. Accurate data are imperative for the health
team to adjust medication, problem solve, and recommend
lifestyle (activity, stress, nutrition) modications for the
patient.
Steps for Self-Monitoring of Blood
Glucose
There are several necessary steps to assure accurate
data from SMBG. To assess a patient’s understanding
of SMBG knowledge, an explanation of the practical
aspects of the procedure is imperative. Table 1 contains
points to consider for successful SMBG and lists several
important steps that should be instituted for SMBG.10–13
Specically, proper use of the strips and general
procedures for meter handling must be understood
appropriately in order to obtain useful data. Since there
are a multitude of meters available on the market, the
information in Table 1 applies to general aspects of
SMBG and user manuals for each individual meter can
be consulted for specic functions, error messages, and
setting date and time. For some meters, the accuracy
can be affected by interfering substances (medication),
temperature, hematocrit level, and user technique.14
In addition, the accuracy of SMBG meters available
has been recommended to produce results within a
20% margin of error.13 Recognition of meter accuracy
variability is important, as many patients will retest
SMBG, obtaining different results that can create concern.
Table 1.
Strip and Meter Handling for Self-Monitoring of
Blood Glucose10–12
Meter and test strips should be handled with clean, dry hands.
Test strips are for single use and unique for each meter.
Test strips must be kept in the original canister, as any moisture
can affect the integrity of the strip, and the containers should be
kept closed. Check for expiration date.
Strips can be tested for accuracy with control solution provided
initially with each meter and should be checked for expiration
date. The control glucose range for the strips appears on the
canister.
Some meters require coding with each canister. Many of the
newer meters do not require coding.
The amount of blood required is usually ver y small.
Many meters easily pull the blood drop into the end of the strip.
Inadequate sample can be a source of error.
Keep meter and supplies in a cool, dry area, not in the car or in
sunlight.
Bring meter into ofce visits with diabetes educator or primary
care provider to test the accuracy comparatively.
Lancing procedures for SMBG require the patient to
fully understand the appropriate steps for successful
blood obtainment (Table 2).15,16 Most SMBG meters come
with some type of lancing device. It will be important
for the patient to demonstrate how to adjust the depth
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Self-Monitoring of Blood Glucose: Practical Aspects Kirk
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J Diabetes Sci Technol Vol 4, Issue 2, March 2010
Blood sample size can also be a factor for many individuals,
especially if there is lancing difculty or lack of blood
ow. Sample size requirement for some meters is as small
as 0.3 μl. Newer SMBG devices deliver results very quickly,
averaging around ve seconds or less. For the vision
impaired, the size of the screen will need to be evaluated
with a variety of digital output reading font sizes and
information that is available. Some meters contain very
sophisticated features such as food/medication/activity
tracking, premeal and postmeal SMBG “tagging,” and
low blood glucose alerts. The option of using a talking
meter that provides verbal guidance on each step in the
SMBG process is also available. A comprehensive guide to
SMBG devices including size, weight, sample size required,
alternative site testing approval, memory features, warranty,
and other meter aspects are available annually at the
beginning of each year in a resource guide published by
the ADA.13
Cost is a major factor for many patients and often times
becomes the primary factor for SMBG meter selection.
Insurance coverage varies widely in the amount of
copay required and whether a deductible has to be met
rst before a percentage of the supplies are covered.
Some insurance companies will only cover a specic
SMBG meter and supplies, giving the patient no
alternative unless they want to pay for a different device
out of pocket. For many insurance coverage plans,
mail order can be an option to cover the meter, strips,
and lancets as durable medical equipment and will not
factor in under the patient’s prescription benet coverage.
Documented medical necessity can help reimbursement
for exceptions.
Management of Self-Monitoring of Blood
Glucose
Management of SMBG depends on the patient’s level
of diabetes education and/or a person’s general ability
to understand the necessary basic steps for SMBG.
The application of SMBG results for self-management is
necessary for successful diabetes outcomes.17 Goal setting
from a health care and patient team approach can also
be useful as action items for SMBG results. For example,
if the results of SMBG show a consistent pattern of high
fasting glucose levels, then medications that target liver
output of glucose might be helpful. Postprandial glucose
levels (two hours after eating) provide information
regarding the impact of food intake on blood sugar.
Diet modication or medication (some orals or mealtime
insulin) may be useful therapies.
of the lancing device to avoid bruising while effectively
acquiring an adequate blood sample. Alternative sites
other than the nger can be used with many meters;
however, blood sample obtainment can often be
challenging without instruction. There are also lancing
tools that have multiple lancets that are inserted into a
device that rotates a cylinder and provides an alternative
to handling individual sharps.
Table 2.
Lancing Procedure for Self-Monitoring of Blood
Glucose13,15
Site preparation: Clean area with warm, soapy water and dry.
Food residue can be a source of false high blood sugar values.
Lancet devices to obtain blood can vary and all use a lancet to
prick the skin. Thin, sharp lancets are more comfortable. Lancets
should not be reused or cleaned, as they quickly become dull.
Depth set ting on the lancet device controls the penetration of
the stick and can be adjusted for best comfort and size of blood
sample. Most meters require very small samples—less than a
small teardrop.
Lancet should be applied rmly to the clean, dry nger, but not
with force.
Sides of the nger should be used, as there is less pain.
Use of the third, fourth, and fth digits may be preferable to
spare index nger and thumb.
Alternate test sites (upper arms and thighs) are approved for
many meter s. Finger tips or the outer palm are preferred and are
more accurate.
Obtainment of blood sample should be a gentle “milking” from
the base of the nger to the lanced tip. Pressure directly on the
site of lancing is not recommended.
Disposal of lancets and SMBG testing supplies should be done
according to local laws for sharps. In many locations, a hard
plastic container with a screw top can be disposed of in the
household trash.
Choosing a Self-Monitoring of Blood
Glucose Device
There are several considerations for pairing a meter
with each patient. Assessment of the patient’s ability to
follow the necessary steps to successfully obtain a SMBG
reading will be essential. Dexterity is a very important
factor to consider. Some meters facilitate the use of
strips that are contained with multiple use containers
or “drums” that load much like a roll of lm into a
camera. Other meters contain multiple blood glucose
strips that are in the form of a circulating wheel that
rotates and eliminates the need to handle individual test
strips. Many SMBG meters have strips that “wick” the
blood sample into the end of the strip, allowing visual
inspection to assure an appropriate sample is obtained.
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J Diabetes Sci Technol Vol 4, Issue 2, March 2010
The role of physical activity and diet will be needed to
assess how to appropriately adjust self-management.
Treatment should be outlined to include goal setting
for self-care behavior.18 Specic schedules for SMBG
will vary for each patient. Short periods of intense SMBG,
before and after each meal and at bedtime, will provide
data to identify glucose patterns. This can be an
important adjunct to A1C to distinguish between
fasting, preprandial hyperglycemia, and postprandial
hyperglycemia. Alternatively, patients may use a staggered
schedule of checking at various times of day throughout
the week. For example, the use of a preprandial
and two-hour postprandial SMBG gives the patient
immediate feedback on their food choices for that meal.
Postprandial spikes may be an independent risk factor
for diabetes complications, even when glycemic control
appears to be satisfactory.19 Useful tips for health
care providers and patients are outlined in Table 3.
Careful consideration should be given to assessing the
patient’s ability to comprehend and retain the procedure of
SMBG that can often be technical. Attention to literacy
and numeracy skills will be an equally important step
in successful SMBG.20 Patient demonstration of SMBG to
the diabetes educator or health care provider is critical.
patient and the health care provider should be agreed upon
to assure periodic assessment of SMBG timing, accuracy
of testing, and goals. For example, when medicine dose is
being adjusted, more frequent SMBG may be needed to
assure response to therapy. Once therapy is established,
SMBG can often be altered to accommodate patient
schedules. Targeting blood glucose uctuations around
meals or increased activity can provide useful information.
There is also the option of a continuous glucose
monitoring system (CGMS). Through a sensor that is
inserted subcutaneously, the patient wears the CGMS for
an extended period of time (usually 3 days) to capture
blood glucose levels day and night.13 While CGMS is
an ideal option to monitor blood glucose spikes and
potential lows, insurance coverage is variable, and
interpretation of the data will be necessary by a qualied
individual (diabetologist, certied diabetes educator, or
endocrinologist).
Other Summary Points
Diabetes requires self-management and adherence to
treatment guidelines such as those recommended by the
ADA; among these is regular SMBG to monitor success
with the diabetes treatment plan. The cost-effectiveness
of SMBG has also been questioned, and insurance
coverage or affordability of glucose test strips must be
considered.21 Some research has shown that providing
SMBG devices at no charge can improve the rate of
testing.22 Self-monitoring of blood glucose can serve
an important role in improving patient knowledge of
glucose levels and the effects of different behaviors on
blood glucose outcomes.
Acknowledgment:
The authors thank Carol Hildebrandt for her expertise in editing this
manuscript.
Disclosures:
Julienne K. Kirk is a diabetes educator/speaker for Novo Nordisk
and Lilly. Jane Stegner is a contracted trainer for Abbott, Animas,
and Roche.
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Table 3.
Tips for Successful Self-Monitoring of Blood
Glucose Teaching
Use simple and specic steps at the patient’s level of
comprehension.
Be sure the patient can demonstrate the steps for SMBG.
Give your patient written recommendations for frequency and
times of testing and desired results.
Obser ve SMBG procedure at follow-up visits.
Ask the patient to assess the relationship of SMBG with exercise,
food, medications, and stress.
Specif y which SMBG values are most problematic (especially
low blood glucose) and discuss solutions with the patient.
Acknowledge the patient for goals achieved with SMBG.
Tools, such as SMBG, can help patients with glucose
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