Collection/Processing Instructions

Patient should fast a minimum of 8 hours. Draw a fasting blood sample before administering glucose load dose. Administer 100g oral glucose load dose and draw blood after 1, 2 and 3 hours. The glucola (oral glucose load) must be consumed within a 5 minute interval; sipping water is permitted. Separate serum or plasma from cells within 60 minutes of venipuncture. Refrigerate if specimen are collected in tube other than gray top. Whole blood specimens in gray top tubes are stable for up to 72 hrs in the refrigerator.

Patient Preparation: The test should be performed on patients who are otherwise healthy and ambulatory (not hospitalized). Ideally the test should be performed in the morning after at least three days of unrestricted physical activity and diet adequate in carbohydrate intake (at least 150 g daily carbohydrate). The patent should fast for a minimum of 8 hours not exceeding 12 hours before the test. Water is permitted during this fasting period. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing. Glucola (oral glucose load) will be administered to patient by phlebotomist and must be consumed within a 5 minute interval; sipping of water is permitted. After consuming the glucose load the patient will be directed not to smoke, chew gum, eat and consume caffeine-containing beverages and have minimal activity during the testing phase. Patient will be permitted to drink small sips of water and allowed to leave the laboratory area during the testing phase. However the patient will be required to remain on clinic or hospital facility grounds. In addition the patient will need to return back to the laboratory for multiple blood collections at one, two and three hour post administration of glucola, a reminder slip with the appropriate times will be given to the patient by phlebotomist.

Note: The patient will be advised by the phlebotomist that if any adverse symptoms develop (i.e. nausea, headache, dizziness or vomiting) the patient should report immediately back to the laboratory. At that point it will be determined if testing will continue or if medical attention is needed.  

For details refer to Gestational Diabetes-Glucose Tolerance