Includes Fasting, 1-Hour, 2-Hour glucose
Patient Preparation Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.
Preferred Specimen(s) Three – 1 mL plasma specimens collected in fluoride/EDTA Tubes
Instructions Immediately after a fasting specimen is obtained, have patient ingest a 75 g load of glucose. Draw subsequent specimens 1 and 2 hours later. Label each with the specific draw time. For children, the glucose load is 1.75 g glucose per kg ideal body weight, up to 75 g (pounds/2.2 = kilograms). See table below.
Weight of Patient (kg) g of glucose
| 10.9-14.9 | 22.5 |
| 15.0-19.4 | 30.0 |
| 19.5-23.5 | 37.5 |
| 23.6-28.1 | 45.0 |
| 28.2-32.2 | 52.5 |
| 32.3-36.7 | 60.0 |
| 36.8-40.8 | 67.5 |
| >40.8 | 75.0 |
Transport Container Plastic screw-cap vials
Transport Temperature
- Ambient 5 days,
- Refrigerated 14 days
Reject Criteria
- Gross hemolysis
- Serum
- Anticoagulants other than fluoride/ oxalate
Methodology Hexokinase
Clinical Significance This test is used for the routine diagnosis of diabetes in children and the non-pregnant adult. For pregnant females see test “Glucose Tolerance Test, Gestational, 4 Specimens (100 g)”. For appropriate interpretation of this test, the patient must fast overnight and ingest a 75 g load of glucose. Immediately after, a fasting specimen is obtained. For children, the glucose load is 1.75 g/Kg of body weight, up to 75. The diagnosis of diabetes is made if the fasting glucose is .126 mg/dL or if the 2-hour specimen is .200 mg/dL.