A. Blood Glucose (Random)
Pros
1. Can be done at any point of time
2. Can be used to monitor new therapeutic outcome
Cons
Results reflect glucose levels only at the time of testing
B. Blood Glucose (Fasting)
Pros
1. Crucial for detecting hypoglycemic state
Cons
Results reflect glucose levels over the past 12 hours and needs fasting of 10 to 12 hours
C. Blood Glucose (Postprandial)
Pros
1. Indicate whether glucose levels are maintained 2hrs post meal
Cons
Results are affected by the type and time of food consumption
D. HbA1c
Pros
1. Identify and monitor the diabetic state.
2. Results reflect the blood glucose level over the past three months
3. Can be done at any point of time without the need of a fasting state
Cons
Not preferred during pregnancy and in cases of hemolysis, heavy bleeding or anemia
E. Fructosamine
Pros
1. Allows to check glucose control for the past 2 to 3 weeks
2. Useful test during pregnancy or for patients with kidney disorders
3. Helps to monitor effectiveness of glucose control over a few weeks
Cons
Results are affected by total protein and albumin levels
F. Blood Ketones
Pros
1. Monitors blood glucose as well as blood ketone levels.
2. Helps detect diabetic ketoacidosis
Cons
Not effective to diagnose diabetes, only to monitor complications
G. Oral Glucose Tolerance Test
Pros
1. It is helpful in diagnosing gestational diabetes
Cons
Not helpful to indicate hypoglycemic state and cannot be used as a confirmatory test
What is Alc?
Alc, also called 'hemoglobin Alc' (HbA1c), is a modified form of hemoglobin. Hemoglobin is an important
component of Red blood cells. It is responsible for carrying oxygen to the tissues of the body. Tissues
without a regular supply of oxygen can be damaged and may ultimately die, Approximately 90% of the
hemoglobin is hemoglobin A (HBA).
HbAlc is formed when glucose molecules attach to HbA molecules in a process known as glycosylation.
The HbAlc test is currently one of the best ways to check whether diabetes is under control.
However, HbA1C testing should not replace daily blood glucose monitoring: but in combination with daily
readings, the Alc test helps the doctor determine how well a current diabetes treatment plan is working,
People with diabetes should have their Alc tested every three months; if blood sugars are fairly stable at near normal levels,
twice a year may be enough.
Monitoring Hemoglobin A1C is important for a number of reasons. First, glucose molecules compete with
oxygen when binding to hemoglobin in red blood cells. If the glucose levels are too high, the tissues of
the body don't receive enough oxygen, which could ultimately lead to damage or death of the cells. This
is how many "secondary" medical problems arise. Another reason for monitoring hemoglobin Alc is that
it represents more accurate information for blood glucose levels over a period. HbA1c values represent
the "average" glucose level for the entire lifespan of the red blood celli.e., about 120 days.
American Diabetes Association (ADA)
There is a mathematical relationship between Alc and average glucose level in the blood. Thus,
reporting of the A1c (units of glycated hemoglobin levels) in terms of estimated average glucose levels
(mg/dL or mmols/dL) is considered appropriate.
ADA Recommends
The Alc test is to be performed at least two times a year in patients who are meeting treatment goals
(and who have stable glycemic control).
The Alc test is performed quarterly in patients whose therapy has changed or who are not meeting glycemic
goals. Use of point-of-care testing for A1C allows timely decisions on therapy changes, when needed.
Glycemic Goals in Adults
Lowering Alc to below or around 7% has been shown to reduce microvascular and neuropathic complications
of type 1 and type 2 diabetes. Therefore, for microvascular disease prevention, the Alc goal for non-pregnant
females, in generalis < 7%
The goal is an Alc of 7% for most patients and an A1c of 6% for patients who are not prone to hypoglycemia.
ADA recommends screening all adults for diabetes who are overweight and have additional risk factors, such
as a family history of diabetes, high blood pressure or abnormal lipid levels. Adults who do not have any of
these risk factors should be tested at the beginning of age 45.
The goal for glycemic control should be as low as feasible without undue risk of adverse events,
like hypoglycemia.
Alc Vs Blood Glucose Testing
Blood Glucose Test
Blood glucose tests are the conventional methods for determining glucose concentration in the blood.
These standard tests reflect blood glucose levels only at the moment of the tests.
A1c is the glycated form of hemoglobin (HbA1c) in the red blood cells. These cells have a life span
of 2-3 months. Thus evaluation of Alc in the blood gives an estimate of blood glucose level over a
period of three months. Here, a significant point is that the amount of glucose attached to the hemoglobin
is proportional to that present in the system.
Thus, while the fasting blood glucose tests give you the current glucose levels in your blood, Alc test
gives an overall picture of the levels over a period of about three months. Blood glucose tests are not
a good indicator of how a person is controlling his/her blood glucose levels.
Alc tests give more accurate account of the blood glucose levels and are therefore reliable.
Estimation of Alc levels also helps the doctors, to understand the course of the disease, to decide
about the medications and to monitor long term prognosis.
What is Fructosamine test?
Fructosamine is a stable ketoamine formed when glucose combines with the amino group of proteins,
usually albumin. Serum albumin is the most abundant protein present in blood which ranges from 3,5g/dl
to 5g/dl. It has a half-life of 18-21 days.
In fructosamine test, the concentration of serum fructose (elevated in diabetes indicate the degree of
glycation with albumin. And this allows to identify poor glucose control more rapidly than other tests,
1.e., short-term hyperglycemia. The test is a biomarker that reflects average glycaemic level of the
preceding 2-3 weeks and helps to control the blood glucose level in diabetes.
Glycated albumin has been a more promising marker than HbA1c for the assessment of glucose control
due to its higher rate of glycation than HbAlc. It is advantageous in people with diabetes and chronic kidney disease, and for those who are on hemodialysis or peritoneal dialysis.
Clinical utility of fructosamine test is high as it provides information regarding short-term glucose control
which is important in conditions like pregnancy. It is also proposed as a suitable parameter to screen
gestational diabetes, as HbAlc test cannot be relied upon due to physiological changes that occur in pregnancy
The short term monitoring through fructosamine test is beneficial to observe rapid Metabolic alterations
or changes in diabetes treatment. It also helps to analyse the effectiveness of diet, exercise and medication
after a few weeks rather than months, especially if they were made recently.
Fructosamine test is able to discriminate well between individuals with and without diabetes. Future
prospects suggests that there may be a relationship between the level of fructosamine and risk to develop
diabetic complications, myocardial infarction and stroke.
