Differences between Oral glucose tolerance test and Oral glucose challenge test
1.
2. outline
• Introduction
• History of OGTT and OGCT
• OGTT and indications
• OGTT procedure and result interpretation
• OGCT and it indications
• OGCT procedure and result interpretation
• Gestational diabetes
• Contrast between OGTT and OGCT
• Conclusion
• References
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4. History OGTT and OGCT
• The glucose
tolerance test
was described
by Jerome W.
Conn.
1923
• The test was on
the previous
work by ATB
Jacobson in
determing that
carbohydrate
ingestion result
in blood glucose
fluctuation.
1913
• The WHO and
organizations
interested in
diabetes agreed
on a standard
dose and
duration.
1970
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5. OGTT
• OGTT is a test that access the body ability to tolerate a
measure quantity of glucose.
• Rate of glucose absorption, ability of beta cell to secret insulin
and property of the insulin to decrease blood glucose level
determine the extent of glucose tolerance.
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6. 10/25/2020 6
Indications
• Patient with family history of
diabetes
familial
• Patient with delay wound healing.
Injury
• With transient glycosuria during
pregnancy
Gestation
• Someone with recurrent vaginal
yeast infection
Infection
• Patient showing evidence of
neuropathy and retinopathy. Of
unconfirmed origin
Idiopathic chronic
complications
7. Patient prep
• The patient is instructed to eat good carbohydrate diet for
3 days prior to the test.
• The patient should avoid some certain drugs for 2 days prior to
the test
• Patient should avoid smoking.
• Streesful exercise is to be avoided prior to test
• The will fast over night.
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8. procedure
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1. A zero time blood is drawn and urine is
also collected at same time as fasting
sample.
2. Glucose solution (75gm of anhydrous
glucose dissolved in 350ml of water)
will then be given to a patient to drink
within 5min time frame.
3. Blood and urine will be collected at
hourly interval in space of 2hrs
4. Plasma glucose is estimated on each
blood sample and urine will be analyze
for the presence of glucose.
9. Result interpretation
• Fasting plasma glucose should be less than 5.6 mmol/L. value
between 5.6 and 6.9 mmol/L indicate pre-diabetes, and value
above 7.0 mmol/L are diagnostic of DM
• For 2 hour GTT; glucose level below 7.0 mmol/L is normal
and value above 10 mmol/L confirm a diagnosis for DM
• Glucose level between 7.8 and 11.1 mmol/L indicate “impaired
glucose tolerance”
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10. OGCT
• It access the ability body to clear off a measure dose of
glucose in a specific time.
• OGCT is a random test.
• It is done between 24th to 28th week of pregnancy.
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12. OGCT procedure and result interpretation
• Patient is ask to drink 50mg of glucose solution.
• Blood is drawn 1 hour later for glucose estimation.
Result interpretation
• Glucose level <140mg/dL (7.8 mmol/L), is negative no further test
needed.
• The test is positive if glucose level is >140mg/dL (7.8mmol/L), and
OGTT will be done the next day to confirm GDM
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13. Gestational diabetes (GDM)
• GDM, is a type of diabetes which develops during the pregnancy
• This occure as a result of placental hormones (progesterone,
Placental lactogen, growth hormone and corticotropin releasing
hormone) interferances with Insulin action.
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14. Complications of GDM
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GDM
Pre-
enclapmsia
Macrosomia
>4000g
Birth
trauma
Hyperbil
irubinem
ia
Neonatal
hypoglyce
mia
hyperglycaemia
15. Differences between OGTT and OGCT
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OGTT
Not a random test
It rule out all
diabetes type
It is WHO
recommended
Test duration is
two to three hours
OGCT
Is a random test
Is done to rule out
only gestational
diabetes
Only recommended
by ACOG.
Test duration is
one hour
