How is a glucose assay performed?

Updated: Jul 22, 2021
  • Author: Setu K Patolia, MD, MPH; Chief Editor: Sridevi Devaraj, PhD, DABCC, FAACC, FRSC, CCRP  more...
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A glucose assay can be performed in human serum, plasma, urine, or cerebrospinal fluid (CSF), as follows:

  • For fasting glucose testing, collect the blood sample in the morning after an overnight or 8-hour fast
  • For postprandial glucose testing, collect the blood sample 2 hours after a regular meal
  • For oral glucose tolerance testing, after oral intake of 75 g of glucose, collect blood samples at 1 hour and 2 hours or just 2 hours
  • For gestational diabetes testing, parameters are 1 hour after 50 g of glucose and 0, 1, and 2 hours after 75 g of glucose or 0, 1, 2, and 3 hours after 100 g of glucose [5]

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