In addition to the collection of capillary blood , oral glucose tolerance test and iv can provide accurate information regarding the operation and trends in carbohydrate metabolism of the patient.
Oral glucose tolerance test measured following ingestion of a carbohydrate metablismul substantial amounts of glucose. ( Pulvis, 75-100 g of glucose dissolved in 300 ml of water , concentration of 25 % , to be drunk within 5 minutes) .
The body will quickly absorb dose , triggering increased plasma levels of glucose and its peak 30 minutes – 1 hour of ingestion.
The pancreas will respond by releasing insulin to bring blood sugar levels to normal within 2-3 hours after ingestion .
During this time it is appropriate to monitor blood sugar levels in the blood and urine tests to detect evaluate insulin secretion and the body’s ability to metabolize glucose.
Glucose tolerance test should always be preceded by proper preparation of the patient. 3 days before , he must have a diet rich in carbohydrates .
The test is performed in the morning on an empty stomach ( fasting ) after at least 8 hours of sleep caloric , when venous blood sample collected first .
Interpretation of results is based on glucose values recorded after 2-3 hours after ingestion .
During this time the patient should be monitored and observed for signs and symptoms of hypoglycemia / hyperglycemia , nervousness , weakness .
Iv glucose tolerance test is carried out on patients who can not orally ingest glucose . (patients with chronic malabsorption , gastrectomy , etc. ) .
The test measures blood glucose after iv administration of 50% glucose infusion for 3-4 minutes.
Glucose tests will be collected at 30 minutes , 1 hour , 2 hours , and 3 hours after glucose administration .
After an immediate rise to blood glucose levels 300-400mg/dl ( accompanied by glycosuria ) blood sugar levels will return to normal within 1 hour , 1 hour and a quarter .
If the 2-3 hours after administration of glucose , its level returns to normal , confirming the suspicion of diabetes.