Glucose - 3 hour

Panels that include this biomarker

• Gestational Glucose Tolerance Diagnostic Test (Three-hour, ACOG Recommendations) 102004

  4 analytes · Serum · Fasting not stated · Turnaround Within 1 day

  Method and collection

  Method

  Enzymatic

  Preparation

  For three days prior to the test, patients should eat an unrestricted diet of 150 or more grams of carbohydrate and be permitted unrestricted physical activity. Patients should be instructed to eat and drink nothing except water for at least eight hours and not more than 14 hours before the test. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing.

  Collection

  Draw a fasting blood sugar before administering 100-gram glucose, and draw blood at one, two, and three hours. The subject should remain seated and not smoke throughout the test. Submit 1 mL serum or plasma for fasting, one-hour, two-hour, and three-hour specimens. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label each tube with patient's name and collection time interval (i.e., fasting, one-hour, two-hour, and three-hour).

  Reference notes

  See table. Specimen* Plasma or Serum Glucose Level (Carpenter and Coustan Conversion) Plasma Glucose Level (National Diabetes Data Group Conversion) *The diagnosis of GDM can be made based on the result of the 100-gram, three-hour oral glucose tolerance test, for which there is evidence that treatment improves outcome. Either the plasma or serum glucose level established by Carpenter and Coustan or the plasma level designated by the National Diabetes Data Group is appropriate to use. A positive diagnosis requires that two or more high thresholds be exceeded. The Carpenter and Coustan conversion is used to establish Labcorp reference intervals. Fasting 70−94 mg/dL 70−105 mg/dL One-hour 70−179 mg/dL 70−190 mg/dL Two-hour 70−154 mg/dL 70−165 mg/dL Three-hour 70−139 mg/dL 70−145 mg/dL

  Labcorp catalog page

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