Question

Describe the graph below.

Glucose Tolerance Curves Blood Glucose Concentration (MM) 60 90 120 Time (minutes) - Standard Control ---Patient B - Patient A Figure 2: Glucose tolerance curve of each patient sample at various time intervals including the standard control.

Answer 1

INTRODUCTION:

Glucose tolerance test is done to test the ability to utilise caebohydrates.

Steps included in Glucose tolerance test:

Initially fatsing blood glucose levels are estimated.

A loading dose of glucose is given.

The blood glucose levels are estimated at regular intervals of time after the glucose load.

A graph is plotted with Blood glucose levels on vertical axis against time intervals on horizontal axis.

The curve so obtrained is called as Glucose tolerance curve.

DESCRIPTION OF GRAPH:

1. Standard control curve

• Fasting blood glucose (zero hour sample) is 90 mg/dl, which is well within the normal range(60-100mg/dl or 6-10mM).
• There is rise in the blood glucose level after glucose load and the peak value is observed at 60 minutes. This is due to absorption of glucose from the intestine.
• Insulin is released upon increase in the blood glucose level.
• As glucose utilisation is prompted by released insulin the normal blood glucose level is acheived at 120 minutes.

2. Patient A : Lag curve

• In Patient A curve a sudden increase in blood glucose level after 30 minutes is due to delay in insulin mechanism coming into action.
• Fasting blood glucose is normal.
• Rapidly increases within 30 minutes and exceeds renal threshold.
• Blood glucose levels return to normal rapidly and completely.
• This type of curve is obtained during pregnancy, early diabetes, hyperthyroidism.

3. Patient B: Diabetic-non treated

• Patient B curve indicates the Diabetic curve (Non treated).
• Fasting blood glucose level is higher than normal.
• The highest level is achieved at 90 minutes.
• The highest level exceeds the renal threshold.
• The blood glucose level does not return to normal range even after 120 minutes(2 hours) because of insulin defeciency in diabetis mellitus patients.
• In conditions of insulin defeciency, blood glucose levels are elevated due to impaired utilisation of glucose.