Haemoglobin A1C
With the new NHS guidelines on diabetes diagnosis being
issued to doctors this month, doctors have been instructed to change from their
current testing method for those thought to have type 2 diabetes to using the
HbA1c test.
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| Haemoglobin A1C |
Although the HbA1c test is more expensive than the oral
glucose tolerance test, it is expected that patients will prefer this method,
especially as it should offer an earlier diagnosis and help prevent more
complications from the condition later in life.
Diagnosing prediabetes with a combination of glycated
haemoglobin and impaired fasting glucose may be a more effective predictor of
progression to diabetes than either test alone, Japanese researchers found.
According to them, introduction of the new HbA1c criterion
in addition to the assessment of fasting plasma glucose could efficiently
target patients who are most likely to progress to diabetes and allow for early
intervention.
Relying on HbA1c levels between 5.7% and 6.4% to diagnose
prediabetes has been controversial, as explained by the researchers, as many
patients who had been diagnosed on the basis of impaired fasting glucose are
reclassified as not having the disorder.
That led some to suspect that screening by HbA1c alone may
miss a large number of prediabetic patients. The researchers also found that
screening by HbA1c alone missed 61% of the 2,092 prediabetic patients diagnosed
by a combination of the screens.
However this particular study done by the Japanese
researchers was limited by the potential for selection bias, due to the fact
that study participants were those who went for medical checkups, and might be
the ones those who pay more attention to health than the general public.
Still, the researchers concluded that the proper collaboration
of the two tests could target individuals most likely to progress to diabetes
and allow for early intervention.
what is a1c test
The A1C test also called the HBA1C test is used to monitor
the glucose control of diabetic patients over time. The goal of patients with
diabetes is to keep their blood glucose levels as close to normal as possible.
This helps them minimize the complications caused by
chronically elevated glucose levels, such as progressive damage to organs like
the kidneys, eyes, cardiovascular system, and nerves. Persistent elevations in
blood sugar and, as a result, HbA1c increase the risk for the long-term
vascular complications of diabetes such as coronary disease, heart attack,
stroke, heart failure, kidney failure, blindness, erectile dysfunction,
neuropathy like loss of sensation, especially in the feet, gangrene, and gastro
paresis. High levels of A1C also increase the risk of short-term complications
of surgery such as poor wound healing.
The A1C test gives a picture of the average amount of
glucose in the patient’s blood over the last few months. This result can help
the patient and the doctor to know if the measures taken to control the
patient’s diabetes are successful or need to be adjusted. The A1C test may be
ordered several times while diabetes control is being achieved, and then
several times a year to verify that good control is being maintained.
The report for a patient’s A1C test also may include an
estimated Average Glucose (eAG), which is a calculated result, based on one’s
A1C
levels. The purpose of reporting eAG is to help you relate
your A1C results the everyday glucose monitoring levels. The formula for eAG
converts percentage A1C to units of mg/dL or mmol/L so that it can be compared
to one’s glucose levels from home monitoring systems or laboratory tests. It
should be noted that the eAG is still an evaluation of the patient’s glucose
over the last couple of months and it will not match up exactly to any one
daily glucose test result.
One should keep in mind the following before getting the A1C
test done. If the patient is hemoglobin variant, like sickle cell hemoglobin
the result shows a decreased amount of hemoglobin A. And if the patient has
anemia, or heavy bleeding, the A1C test results may be low. If the patient is
iron deficient, then there can be an increased A1C measurement. If the patient
had a recent transfusion, then the A1C result will be falsely increased as the
blood preservative solutions contain high glucose levels. The A1C test results
can be unreliable in some other circumstances such as, after blood loss, for
example, after surgery, or high erythrocyte turnover; in the presence of
chronic renal or liver disease; after administration of high-dose vitamin C; or
erythropoetin treatment.
A1C test helps the patient and the doctor to find whether the self-testing results are going on correctly and to confirm whether the treatment plan is working or needs modification. If the A1C result is not within the target set by the doctor, then the treatment can be changed accordingly. Healthy food choices and good strict diabetes care can make a difference in diabetes control. This helps the patient in maintaining a healthy blood glucose level and many diabetes complications can be avoided or postponed. Though the patient is getting the A1C test done every 3 months, regular home blood glucose level test shouldn’t be avoided. Regular checking is very much needed for immediate glucose level correction treatment.
A1C level measurement
A1C level measurement by each lab may use a different
technique, so the test result from different labs may give different result for
same blood sample. For the same blood sample different labs might give
different results. So if the lab is changed for A1C test, then the test numbers
may need to be read differently
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