Test Library

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.