Posted on: Aug 08, '08

TRUE SUGAR CHECK
FASTING & PP BLOOD SUGAR MIGHT NOT BE THE TRUE INDICATION OF SUGAR LEVEL, FOR ACTUAL PICTURE OF DIABETES –
***GLYCOSYLATED HAEMOGLOBIN(HBA1C)****
Ceirculating Haemoglbin (Hb) in adults consist of HBA (97%), Hba2 (2.5%) and HBF (0.5%). Hba contains a number of minor Hb (HbA1A, HbA1B, & HbA1C), collectively known as HbA1. HbA1C is the direct combination of glucose and average concentration of glucose in the blood. In anormal person, about 4-6% of HbA is glycosylated, in the diabetic, the percentage of HbA1C increases depending upon the degree of hypoglycaemia. This HbA1C accumulates with in the RBCs and exists in this from throughout the lifespan of the red blood cells i.e. 80-120days.Measurement ofHbA1C therefore, reflects the long-term diabetic control over the 2-3 month period to blood collection.
All people with diabetes should have a haemoglobin A1C at least trice a year. People with diabetes should get the test more often if their blood sugar stays too high or their diabetologist/physician makes any change in their treatment plan.
The findings of a major diabetes study, the Diabetes Control and Complications Trial (DCCT), have shown that lowering the haemoglobin A1C number can delay or prevent the development of serious eye, kidney, and nerve disease in people with diabetes. The study also showed that lowering Haemoglobin A1C levels by any amount improves a person’s chances of staying healthy.
Glycosylated haemoglobin (total) is total HbA1C , which comprises (HbA1A, HbA1B, & HbA1C) and is that most laboratories estimate and the HbA1C value is then arrived at by an approximate calculation . This method obviously has several drawbacks thereby affecting the accuracy of the test. The HPLC (Gold Standard for HBA1C) method is the only method that meets all five of the NTH recommended guidelines for the determination of haemoglobin A1C , which include:
NTH recommended guidelines:
1. Specific measurment of haemoglobin A1C
2. Narrow non-diabetic range (4.0% - 6.0%)
3. Highly precise mesurement (<2% - CV’s)
4. Removal of interferences
5. Haemoglobinopathies detected when present
Therapy for diabetes requires long-term maintenance of blood glucose level as close as possible to normal level, minimizing the risk of long-term vascular/neural complications. A single fasting or post-prandial (p.p) glucose level is an indication of patient’s immediate past condition (hours) , but may not represent the true status of blood glucose regulation. This is because blood glucose level is affected by so many factors like, intake of carbohydrates, absorption , metabolism, timing and dosage of anti-diabetic drugs, anxietly and mental stress, activity during the day, interference from many common drugs as also alcohol. HbA1C is not affected by the above-mentioned variables and hence is a true index of the mean true blood glucose.
HbA1C test result are measured by Affinity Column Chromatography, which allow the determination of a calculated mean blood glucose (MBG) reported in mg/dl . This calculation is only possible using the HPLC analytical method and is based on Nathan ET AL. , Linear regression formula. This MBG level reflects the average blood glucose level over the last 3 month period abnormal Hb variants (HBF and some other rate Hb variants) which coelute with HBA1 fractions may give abnormally high values for HbA1C…..
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