Transcript Digital Glucometer


Glucose
› A substance produced when carbohydrates
from food are broken down in the stomach
and intestines during digestion
› Glucose is then absorbed into the blood
stream, where insulin (created in the
pancreas) facilitates its use by the body’s
tissues

A glucose meter (or glucometer) is a
medical device for determining the
approximate concentration of glucose in
the blood.
› It is a key element of home blood glucose
monitoring (HBGM) by people with diabetes
mellitus or hypoglycemia
› A small drop of blood, obtained by pricking
the skin with a lancet, is placed on a
disposable test strip that the meter reads
and uses to calculate the blood glucose
level. The meter then displays the level in
mg/dl or mmol/l.

A small drop of blood is placed on a
disposable test strip that the meter reads
and uses to calculate the blood glucose
level. The conductivity of blood is affected
by the quantity of glucose present. This
biological phenomenon can be modeled
with an electrical circuit. The voltage drop
in the variable resistance is determined by
conductivity of the resistance. When the
conductivity is high, the voltage drop is low,
and when the conductivity is low, the
voltage drop is high. These variations can
be analyzed by a microprocessor (MCU) to
determine the glucose concentration and
display on an LCD.
Steps in Checking a Blood
Glucose
 Step 1

› Body Substance Isolation

Step 2
› Prepare Equipment
› Place lancet in pen
› Place test strip in glucometer

Step 3
› Choose site (side of finger)

Step 4
› Cleanse site with an alcohol swab in circular
motion
› Ensure site is dry prior to poking finger

Step 5
› Hold pen tightly against side of finger and
push trigger to release the needle


Step 6
› You may need to massage the finger to get
blood flow
› Apply test strip to the blood sample
› Test strip will absorb blood and will begin to
“count down”
Step 7
› Remove test strip from blood sample
› Apply direct pressure to puncture site with a
dressing

Step 8
› Apply bandage to puncture site

Step 9
› Record time and reading on the PCR

Step 10
› Remove sharp from glucometer pen, and
› place into a sharps container

The functionality of a blood glucose
meter can be expanded to allow wired
or wireless communication with other
devices such as smart phones, insulin
dispensers or calorimeters. This can be
useful for telehealth applications and
remote patient monitoring. Some
companies offer specific MCUs with
integrated analog blocks and ZigBee®
and proprietary wireless solutions for
glucometers.
Size: The average size is now approximately the size of the palm of the
hand, though some are smaller or larger. They are battery-powered.
 Test strips: A consumable element containing chemicals that react with
glucose in the drop of blood is used for each measurement. For some
models this element is a plastic test strip with a small spot impregnated
with glucose oxidase and other components. Each strip is used once
and then discarded. Instead of strips, some models use discs that may
be used for several readings.
 Coding: Since test strips may vary from batch to batch, some models
require the user to enter in a code found on the vial of test strips or on a
chip that comes with the test strip. By entering the coding or chip into
the glucose meter, the meter will be calibrated to that batch of test
strips. However, if this process is carried out incorrectly, the meter
reading can be up to 4mmol/L inaccuracy. The implications of an
incorrectly coded meter can be serious for patients actively managing
their diabetes. For miscoded meters, the probability of making an
insulin dose error of 2 units is 50%. The probability of making an insulin
dose error of 3 units is 24%, compared to 0.49% when using a no coding
meter. This may place patients at increased risk of hypoglycaemia.
 Volume of blood sample: The size of the drop of blood needed by
different models varies from 0.3 to 1 μl. (Older models required larger
blood samples, usually defined as a "hanging drop" from the fingertip.)
Smaller volume requirements reduce the frequency of unproductive
pricks.

Testing times: The times it takes to read a test strip may range
from 3 to 60 seconds for different models.
 Display: The glucose value in mg/dl or mmol/l is displayed in a
small window. The preferred measurement unit varies by
country: mg/dl are preferred in the U.S., mmol/l in Canada and
Europe. (To convert mmol/l of glucose to mg/dl, multiply by 18.
To convert mg/dl of glucose to mmol/l, divide by 18 or multiply
by 0.055.) Many machines can toggle between both types of
measurements; there have been a couple of published
instances in which someone with diabetes has been misled into
the wrong action by assuming that a reading in mmol/l was
really a very low reading in mg/dl, or the converse.
 Glucose vs. plasma glucose: Glucose levels in plasma (one of
the components of blood) are generally 10%–15% higher than
glucose measurements in whole blood (and even more after
eating). This is important because home blood glucose meters
measure the glucose in whole blood while most lab tests
measure the glucose in plasma. Currently, there are many
meters on the market that give results as "plasma equivalent,"
even though they are measuring whole blood glucose. The
plasma equivalent is calculated from the whole blood glucose
reading using an equation built into the glucose meter. This
allows patients to easily compare their glucose measurements in
a lab test and at home. It is important for patients and their
health care providers to know whether the meter gives its results
as "whole blood equivalent" or "plasma equivalent.“

Clock/memory: All meters now include a clock that is set
for date and time, and a memory for past test results. The
memory is an important aspect of diabetes care, as it
enables the person with diabetes to keep a record of
management and look for trends and patterns in blood
glucose levels over days. Most memory chips can display
an average of recent glucose readings.
 Data transfer: Many meters now have more sophisticated
data handling capabilities. Many can be downloaded by
a cable or infrared to a computer that has diabetes
management software to display the test results. Some
meters allow entry of additional data throughout the day,
such as insulin dose, amounts of carbohydrates eaten, or
exercise. A number of meters have been combined with
other devices, such as insulin injection devices, PDAs, and
even Game Boys.[1] A radio link to an insulin pump allows
automatic transfer of glucose readings to a calculator
that assists the wearer in deciding on an appropriate
insulin dose.
