WHAT ARE THE TESTS USED FOR MONITORING
GLUCOSE LEVELS IN TYPE 1 DIABETES?
Tests for Glucose Levels
Both hypoglycemia and hyperglycemia
are of concern for patients who are receiving insulin.
It is important, therefore, to monitor blood glucose
levels carefully. In general, patients with type 1 diabetes
need to take readings four or more times a day. Patients
should aim for the following measurements:
Different goals may be required for
specific individuals, including pregnant women, very
old and very young people, and those with accompanying
serious medical conditions.
Finger-Prick Test. A typical blood sugar test
includes the following:
-
A drop of blood is obtained by
pricking the finger. (A laser finger-prick device
may be make the test easier for children.)
-
The blood is then applied to a
chemically treated strip.
-
Home monitors are generally used
to provide results.
Home monitors are about 10% to 15%
less accurate than laboratory monitors are and many
do not meet the standards of the American Diabetes Association.
Many experts believe, however, that most are accurate
enough to indicate when blood sugar is too low.
Some simple procedures may improve accuracy:
-
Testing the meter once a month.
-
Recalibrating it whenever a new
packet of strips is used.
-
Using fresh strips. (They are expensive,
however, costing about $.50 each.)
-
Keeping the meter clean.
-
Periodically comparing the meter
results with the results from a laboratory.
Less Invasive or Noninvasive Tests.
A number of noninvasive or less painful tests are
on the market or under investigation. The following
are some examples:
-
A battery-powered wristwatch-like
device (GlucoWatch) measures glucose by sending
tiny electric currents through the skin. It appears
to be accurate at detecting high glucose levels
and has a warning device when this occurs. It is
less effective at identifying low blood sugar levels,
however. Experts believe that, at this point, it
should be used to supplement, not replace, finger-prick
blood tests. It is still being used only in adults.
It takes three hours to warm up and the sensor pads
need to be changed every day. It is also expensive
and unlikely to be covered by many health insurers.
-
One investigational tester claimed
that a new system called Sof-Tact was painless.
The patient holds the device that combines a lancing
device and a meter against the skin. Once a button
is pressed, a small vacuum is created. Blood is
taken and applied to the strip automatically.
-
FreeStyle uses the smallest blood
sample of any current meter and so can be taken
from areas with fewer nerve endings (such as the
forearm). It appears to be nearly painless.
-
Laser devices (Altea MicroPor)
are also being investigated, they create microscopic
pores in the skin, allowing measurement of glucose.
-
Microneedles may eventually be
available that are so small their effect is similar
to a mosquito bite.
-
Infrared technology is being investigated
for noninvasive detection of glucose levels. A number
of devices are in development.
Tests for Glycated Hemoglobin
Hemoglobin A1c (HbA1c), or glycated
hemoglobin, is measured periodically to determine the
average blood-sugar level over the life span of the
red blood cell, which is about eight to 10 weeks. In
general, measurements suggest the following:
A home test (DRx) is now available
for HbA1c that may allow even better monitoring of glucose
levels
Urine Tests
Urine tests are useful for detecting
the presence of ketones, which should always be performed
during illness or stressful situations, when diabetes
is likely to go out of control. The patient should also
undergo yearly urine tests for microalbuminuria (small
amounts of protein in the urine), a risk factor for
future kidney disease.
Eye Examinations
For those on intensive insulin therapy,
experts recommend an eye examination when starting treatments
and every three months thereafter up to a year. |
