|Purpose||estimate blood sugar levels|
Many types of glucose tests exist and they can be used to estimate blood sugar levels at a given time or, over a longer period of time, to obtain average levels or to see how fast body is able to normalize changed glucose levels. Eating food for example leads to elevated blood sugar levels. In healthy people these levels quickly return to normal via increased cellular glucose uptake which is primarily mediated by increase in blood insulin levels.
Glucose tests can reveal temporary/long-term hyperglycemia or hypoglycemia. These conditions may not have obvious symptoms and can damage organs in the long-term. Abnormally high/low levels, slow return to normal levels from either of these conditions and/or inability to normalize blood sugar levels means that the person being tested probably has some kind of medical condition like type 2 diabetes which is caused by cellular insensitivity to insulin. Glucose tests are thus often used to diagnose such conditions.
Tests that can be performed at home are used in blood glucose monitoring for illnesses that have already been diagnosed medically so that these illnesses can be maintained via medication and meal timing. Some of the home testing methods include
Laboratory tests are often used to diagnose illnesses and such methods include
Some laboratory tests don't measure glucose levels directly from body fluids or tissues, but still indicate elevated blood sugar levels. Such tests measure the levels of glycated hemoglobin, other glycated proteins, 1,5-anhydroglucitol etc. from blood.
Glucose testing can be used to diagnose or indicate certain medical conditions.
High blood sugar may indicate
Low blood sugar may indicate
Blood sugar levels can be affected by some drugs and prior to some glucose tests these medications should be temporarily given up or their dosages should be decreased. Such drugs may include salicylates (Aspirin), birth control pills, corticosteroids, tricyclic antidepressants, lithium, diuretics and phenytoin.
Some foods contain caffeine (coffee, tea, colas, energy drinks etc.). Blood sugar levels of healthy people are generally not significantly changed by caffeine, but in diabetics caffeine intake may elevate these levels via its ability to stimulate the adrenergic nervous system.
A level below 5.6 mmol/l (100 mg/dl) 10–16 hours without eating is normal. 5.6–6 mmol/l (100–109 mg/dl) may indicate prediabetes and oral glucose tolerance test (OGTT) should be done for high-risk individuals (old people, those with high blood pressure etc.). 6.1–6.9 mmol/l (110–125 mg/dl) means OGTT should be done even if other indicators of diabetes are not present. 7 mmol/l (126 mg/dl) and above indicates diabetes and the fasting test should be repeated.