Theonset of both types of diabetes can be diagnosed and monitored via OGTT (OralGlucose Tolerance Test) and HBA1c levels. The haemoglobin A1c test measures theamount of glycosylated haemoglobin (haemoglobin bound to glucose) in thepatient’s blood and provides information about your average blood glucoselevels over the previous 2 to 3 months. When haemoglobin and glucosebond, a coat of sugar forms on the haemoglobin.
That coat gets thicker whenthere’s more sugar in the blood. HbA1c tests measure how thick that coat hasbeen over the past 3 months, which is how long a red blood cell lives. Peoplewho have diabetes or other conditions that increase their blood glucose levelshave more glycohaemoglobin (sugar bound to haemoglobin) than normal. HbA1c levelsover 6.5% are suggestive of diabetes. Blood glucose tends to bind itself to thesurface of red blood cells, and the average lifespan of red blood cells isaround 3-4 months, therefore the measuring of the number of red blood cellswith glucose attached to them gives an idea of the blood glucose levels overthe past 120 days. Recommended HbA1c readings fall within the reference rangeof 6.
5 to 7%. This implies that for every 100 red blood cells, 6-7 cells haveglucose attached to them. In labs, the VARIANT™ Haemoglobin Testing System is astate-of-the-art contraption which provides automated diabetes monitoring, betathalassemia for hemoglobinopathy and sickle cell disease. HbA1c testing is mostcommonly used to monitor diabetes, but the test alone is not indication enoughfor the diagnosis of diabetes. HbA1c tests can only be used to diagnosediabetes when coupled with OGTT and the fasting glucose test.
OGTT tests the ability of the body’s cells toabsorb glucose after ingestion of a fixed amount of sugar. In normalindividuals, pancreatic insulin secretion maintains blood glucose within atight concentration range following an oral glucose load. Failure of insulinsecretion, or resistance to insulin action, will result in an elevation inblood glucose. Depending on age, lifestyle and diet, the severity of diabetesvaries from person to person. Glucoseconcentrations vary with age in healthy individuals. The reference interval forchildren is 3.3–5.
6 mmol/L (60–100 mg/dL), which is similar to the adultinterval of 4.1–6.1 mmol/L (74–110 mg/dL) Before the OGTT test is performed,the normal blood glucose level should be 5-6 mmol/L.
However, normal prandialblood glucose levels varies from individual to individual. The variation of theaverage range of normal blood glucose levels are mostly affected by age. Forexample, the normal fasting blood glucose range for premature babies andnew-borns are 1.67-3.33mmol/L and 2.
78-4.44mmol/L.Even new-borns that vary just a few days in age have an effect on the range ofaverage blood glucose levels as the range for new-borns under a day old or aday old is 2.
22-3.33mmol/L but for new-borns more than a day old the range is 2.78-4.44mmol/L.The difference between average blood glucose of a child and adult is even morepronounced.
A child’s average blood glucose ranges from 3.33-5.55mmol/L, whilean adult’s is much higher at 3.89-5.83mmol/L. As a person ages, the bodybecomes less efficient as storing glucose, so for the elderly, the normal rangeis of blood glucose values is higher than an adult’s. Like new-borns, thenormal blood glucose range for the elderly is affected by age. For individualsaged 60 and above, the normal blood glucose range is 4.
44-6.38mmol/L, andincreases to 4.61-6.10mmol/L for those aged 70 and above. After consumption ofa glucose solution, the blood glucose is measured again after 2h. At 2h, thenormal postprandial blood glucose level should be under 7.
8 for non-diabeticadults. For individuals with impaired glucose tolerance, the postprandial bloodglucose level should not be more than 7.9-11mmol/L.
For suffers of diabetes,the usual postprandial blood glucose level should be more than 11.1mmol/L. Thereare also different ranges for glucose found in urine. In a normal non-diabeticperson, no glucose should be detected in urine.
But in the case of diabeticindividuals, glucose is present in the urine and therefore can be measured. Fora child or an infant, the range is higher at 3.33-4.44mmol/L, whereas it islower for adults at 2.22-3.89mmol/L.
The values for glucose present in urinealso depends based on the type of urine collected and tested for the presenceand amount of glucose in it. For random urine, the values should be around 0.1-0.8mmol/L,while for 24h urine, the glucose present in the urine should not exceed 2.8mmol/day.OGTT is predominantly used to diagnose gestational diabetes, which is usuallydone between the 24th and 28th weeks of pregnancy.