OGTT test stands for Oral Glucose Tolerance Test. It is a type of blood test that is commonly used for the diagnosis of diabetes mellitus and some other conditions. In this test, a fasting blood sample is taken first and then...
What is OGTT test?
OGTT test stands for Oral Glucose Tolerance Test. It is a type of blood test that is commonly used for the diagnosis of diabetes mellitus and some other conditions. In this test, a fasting blood sample is taken first and then a standard dose of glucose is given to the patient. Usually, 2-4 blood samples are taken depending upon the type of OGTT such as 2-hour OGTT or 3 Hour OGTT.
What is the difference between OGTT and GTT?
GTT (Glucose tolerance test) is also known as OGTT test. And both test means the same.
What are the uses of OGTT test?
OGTT is indicated for the diagnosis or monitoring of the following conditions:
- Diabetes
- Prediabetes
- Gestational diabetes
- Insulin resistance
- Reactive hypoglycemia
- Metabolic syndrome
- Acromegaly
- Beta cell dysfunction
- Impaired carbohydrate metabolism
- Borderline Fasting blood glucose (Between 100-126 mg/dl) but symptoms indicative of diabetes mellitus.
- H/o macrosomia (big baby >4kg)
- H/o excessive weight gain during pregnancy
- To rule out benign renal glucosuria
- Past history of miscarriage
- Past history of congenital malformations in baby.
How do I prepare for an OGTT blood test?
Follow these simple steps to prepare yourself for an OGTT test:
- Book an appointment: Fix an appointment in a blood testing lab.
- Fasting: 8-12 hours fasting is required for OGTT test. Usually an overnight fasting is done, and blood samples are taken in the morning.
- Food: There is no need to restrict your carbohydrate intake a night before the test. So, you can eat a normal diet weeks or days before the test.
- Medications: Intake of certain drugs affect the result of glucose tolerance test. You may ask your doctor about any drug modification before the test. Drugs that can alter your glucose tolerance test includes:
- Diuretics
- Oral contraceptives
- Anti-convulsant drugs
- Large doses of salicylates etc.
How is an OGTT test done?
The procedure of OGTT test includes the following steps:
- Fating blood sample is collected as a baseline.
- You will be given a standard dose of glucose solution to drink within minutes.
- Dose of glucose may be different depending upon the type of GTT such as 75 gram of oral glucose solution is usually given to adults as per the recommendations of WHO (world health organisations). However, a 50-gm glucose over 1 hour is used for pregnant women to screen for gestational diabetes mellitus. If its is found to be abnormal then a 100-gm glucose over 3 hours can be performed.
- After giving test dose, blood samples are collected at an interval of 30 minutes to 60 minutes.
- Report is available on the same day.
Can I drink water during OGTT test?
Yes, you can drink water during the procedure. However, you are not allowed to eat anything except the glucose solution provided to you during the test.
What are the side effects of OGTT test?
OGTT test is a safe procedure. However, some individuals may experience some side effects such as:
- Nausea
- Light headache
- Sweatiness
- Pain at injection site
- Hematoma due to multiple punctures to locate vein in those where veins are not easily assessable.
How much time taken for OGTT test?
Time taken for OGTT test depends upon the type of OGTT test. Given below table summarizes the type of OGTT test, dose of glucose administered to patient and time taken in different types of OGTT test.
|
Type |
Oral Glucose administered |
Time taken |
|
75 gm over 2 hr OGTT
|
75 gm |
2 hr |
|
100 gm over 3 hr OGTT
|
100 gm |
3 hr |
What is the normal range for OGTT test?
|
|
Normal range
|
Pre-diabetes |
Diabetes |
|
Fasting |
<100mg/dl |
100-125 mg/dl |
>126 mg/dl |
|
2 hr after glucose administration |
<140mg/dl |
140-199 mg/dl
|
>200mg/dl
|
|
HbA1c |
<5.7% |
5.7-6.4% |
6.5% or more |
Gestational diabetes mellitus (GDM) in pregnancy?
Pregnancy is considered as a diabetogenic state. Insulin resistance occur in pregnancy usually around 20-24 weeks of gestation due to the effect of hormones such as cortisol, estrogen and especially human placental lactogen. As a result, glucose level in maternal blood rises and cross the threshold values. This condition is known as Gestational diabetes mellitus (GDM). The main aim of this condition is to maintain uninterrupted supply of glucose to the growing fetus. However, usually after delivery of the baby, Gestational Diabetes mellitus (GDM) subsides.
OGTT test in pregnancy?
The ACOG (American College of Obstetrician and Gynecologist) recommends a two-step method for the diagnosis of Gestational diabetes mellitus. In the 1st step a pregnant woman is administered 50 gm oral glucose solution and blood sample is taken after an interval of 1 hour, this is known as OGCT (oral glucose challenge test). If the blood glucose level is >140 mg/dl, then a 100-gm glucose over 3hour is performed.
OGCT test in pregnancy report analysis?
50 gm over 1 hr OGCT (oral glucose challenge test) report analysis:
|
OCGT screening test |
Normal/NGT |
Abnormal/IGT |
|
1 hr OGCT |
<140 mg/dl |
140 mg/dl or more |
Terms Description:
NGT: Normal glucose tolerance
IGT: Impaired glucose tolerance
OGTT test in pregnancy report analysis?
100 gm over 3 hr OGTT (oral glucose tolerance test) report analysis:
|
Carpenter and Coustan criteria-100mg OGTT |
Normal |
Criteria for GDM |
|
Fasting |
<95 mg/dl |
>95mg/dl |
|
1 hr OGTT |
<180 mg/dl |
>180 mg/dl |
|
2 hr OGTT |
<155 mg/dl |
>155 mg/dl |
|
3 hr OGTT |
<140 mg/dl |
>140 mg/dl |
OGTT test price in Delhi?
Price of OGTT depends upon many factors such as with city and locality and type of OGTT required such 2hr OGTT test or 3hr OGTT test. Different diagnostic centers charges according to the quality of machines they have and various offers that they are providing to their customers.
Ganesh Diagnostic and Imaging centre, Rohini also known as GDIC is currently offering 50% discounts on various tests including OGTT test. We have many branches in different locations of Delhi including Hari Nagar, Yamuna Vihar, Nangloi, Derawal Nagar and Mangol puri. Our centers are NABH and NABL accredited and equipped with modern, highly expensive machines with latest cutting-edge technologies and highly skilled Radiologists and Pathologists.
We follow strict aseptic conditions to prevent transmission of infections.
Glucose Challenge Test (GCT) ₹ 160 - ₹ 80 BOOK NOW
Glucose Customized Post 75g Load ₹ 100
Diabetes Panel Basic ₹ 600
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