Oral Glucose Tolerance Test
By Abdulaziz Massoud Alfaydi
Oral Glucose Definition. Tolerance Test ( OGTT ) Procedure. Curves. Different Types Explain.
DEFINITION The Term Diabetes Mellitus Describes Several Diseases Of Abnormal Carbohydrate Metabolism That Are Characterized By Hyperglycemia. It Is Associated With A Relative Or Absolute Impairment In Insulin Secretion, Along With Varying Degrees Of Peripheral Resistance To The Action Of Insulin.
CONTINUED Glucose Tolerance Test (GTT) Consists Of Drinking (75 To 100 )Grams Of Glucose Solution . .Measuring The Blood Glucose Values Every Hour To Get A Curve . .A 2 Hour GTT Is Used To Diagnosis Diabetes , But A 6 Hour Test Might Also Diagnosis Diabetes Plus Hypoglycemia. .Symptoms Of Hypoglycemia Occur After The 5 Th Hour. .In Healthy Individual The Insulin Response To A
.The
Terminology Normoglycemia - Fasting Blood Glucose 75-
100mg/dL. Impaired Glucose Tolerance: 110-126mg/dL. Hyperglycemia : >126mg/dL.
ABNORMAL HYPERGLYCEMIA. HYPOGLYCEMIA.
10/18/09
6
DIABETES STATUS MONITORING A.Conventiona Glucose-Blood (GOD-POD). -Urine. Benedict reagent. G Y O R 0.5% 1% 1.5% 2->2% GTT: 1.Lab-Oral GTT (OGTT). 2.Clinic-Post-prandial (meal). 7
Factors affecting GTT Concerned with the blood glucose regulation: 1.Metabolic-diet-thiamine. -starvation. -excretion. -liver diseases, infection. 2.Hormones-insulin: -antagonists.
epinephrine,glucagon,glucocorticoids,GH, THYROXIN.
8
Procedure This Is Timed Test For Glucose Tolerance Hour Plasma . A-2 Glucose Test Is Done After Glucose Load To Detect Diabetic Individuals Other Than Pregnant Women . The 3- Hour Test Is Done For Pregnant Women The 4- Hour Test Evaluates Possible Hypoglycemia.
Continued
1- Have Patient Eat A Diet With >150 g Of Carbohydrates For 3 Days Before The Test. Administer 1.75g/Kg Body Weight Oral Glucose Say Dissolved In 250 ml Of Water Allow Him To Drink The Glucose Solution Over A Period Of 5 Minute Time
DRUGS 2-Ensure That The Following Drugs Are Discontinued 3 Days Before The Test Because They May Influence Test Results: A) Hormones , Oral Contraceptives , Steroids. B)salicylates, Anti Inflammatory Drugs. C)diuretic Agents. D) Hypoglycemic Agents. .E) Antihypertensive Drugs And Other Drugs As Advised By The Diabetologist.
CONTINUED 3-A 5ml Sample Of Venous Blood Is Drawn. The Patient Should Fast 12 To 16 Hours Before Testing . 4-blood Samples Are Obtained 30 Minutes , 1 Hr, 2hrs, 3hrs After Glucose Ingestion. 5- Specimens Taken 4 Hrs After Ingestion Are Significant For Detecting Hypoglycemia . 6-Tolerance teste can also be performed for Pentose ,Lactose ,Galactose And D- Xylose.
Possible Interpretation a) Persistent fasting hyperglycemia >140mg/dl Or >7.8mmol/L. b) Persistent fasting normal plasma glucose . c) Patient with overt diabetes mellitus. d) Persistent 2-hour plasma glucose >200mg/dl Or >11.1mmol/L.
Interfering factors 1- Smoking Increases Glucose Levels. 2-altered Diets (Weight Reduction) Before Testing Can Diminish Carbohydrate Tolerance And Suggest ,False Diabetes. Glucose Levels Normally Tend To Increase With Aging. 3-prolonged Oral Contraceptive Use Causes Significantly Higher Glucose Levels In The Second Hour Or In Later Blood Specimens.
continued 4-Infections disease illnesses and operative procedures affect glucose tolerance. .5- Certain drugs a) Corticosteroids. b) Estrogens. c) Heparin. d) Nicotinic acid . e) Phenothiazines. f) Lithium .
CONTINUED STATE
NORMAL
IMPAIRED
DIABETES
Fasting
70-110
110-126 (IFG)
>126
2 Hr(mini GTT)
140
140-200(IGT)
>200
18
curve according to Seale Harris
Time [hours]
0
0.5
Blood glucose [mg/dl]
80 90
1
2
105 90
3
4
5
6
80
80
80
80
1b. Normal Maximum curve
Time [hours]
0
0.5 1
2
3
4
5
6
Blood glucose [mg/dl]
120 135 160 130 110 100 110 105
diabetes
Time [hours] Blood glucose[mg/dl]
0 115
0.5 145
1 180
2 160
3 120
4
5
130 130
6
130
3. Curve with severe diabetes
Time [hours]
0
0.5 1
2
3
4
5
6
Blood glucose[mg/dl]
200 235 265 280 300 295 280 270
4. Diabetes and hypoglycemia
Time [hours]
0
0.5 1
2
3
Blood glucose[mg/dl]
100 160 220 160 85
4
5
6
60
50
85
5. Continuous low values
Time [hours]
0
0.5 1
2
3
4
5
6
Blood glucose[mg/dl]
60
80 100
60
60
60
60
55
6. Pre-hypoglycemia
Time [hours]
0
0.5 1
2
3
Blood glucose [mg/dl]
90
115 140 100 85
4
5
6
80
70
75
7. Mild hypoglycemia
Time [hours]
0
0.5 1
2
3
4
5
6
Blood glucose [mg/dl]
80
120 80
60
80
75
80
80
9. Severe hypoglycemia II
Time [hours]
00.5
1
2
3
4
5
6 7
Blood glucose [mg/dl]
100
170
110
130
170
125
100
100
10. Flat curve
Time [hours]
0
0.5
1
2
3
4
5
6
Blood glucose [mg/dl]
90
90
90
100
90
100
80
90
8. Severe hypoglycemia I
Time [hours]
0
0.5
1
2
Blood glucose[mg/dl]
95
110
120 105
3
4
5
6
100
60
40
60
THANK YOU