One way of interpreting the data collected during a glucose tolerance test is to measure the area under the glucose time curve, based on glucose measurements collected at 30 minute intervals.
Duration of Test |
Glucose Measurements |
Number of Subregions (n –1) |
1 hour |
0 (baseline), 30, 60 minutes |
2 |
2 hour |
0, 30, 60, 90, 120 minutes |
4 |
3 hour |
0, 30, 60, 90, 120, 150, 180 minutes |
6 |
where:
• The initial glucose reading is done on a fasting specimen.
• Glucose readings are in mg/dL. It can be expressed in mmol/L, with adjustments to area under curve to min*mol/L.
• The oral glucose load administered may vary (50, 75 or 100 grams).
• The molecular weight of glucose is 180.16.
area in each subregion =
= (area of rectangular subportion) + (area of triangular subportion)
= ((30 minutes) * (minimum of 2 readings)) + (0.5 * (30 minutes) * (difference between 2 readings))
area under curve in min*mg/dL =
= SUM(areas for all subregions)
area under curve in min*g/dL =
= (area under curve in min*mg/dl) / 1000
Specialty: Endocrinology, Clinical Laboratory
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