oral glucose tolerance test

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oral glucose tolerance test



A screening test for diabetes mellitus (DM), in which plasma glucose levels are measured after the patient consumes an oral glucose load. In screening patients for type 2 DM, measuring fasting plasma glucose levels or checking a hemoglobin A1c level is generally preferable to an OGTT because the former tests are simpler, cheaper, and better tolerated by patients. An OGTT reveals type 2 DM when plasma glucose levels exceed 200 mg/dl 2 hr after drinking a 75-g glucose load. Plasma glucose levels between 140 mg/dl and 199 mg/dl suggest impaired glucose tolerance.

Gestational Diabetes Mellitus

In pregnancy, a modified OGTT is used to screen women with risk factors for gestational diabetes (GDM), including obesity, family history of type 2 DM, age greater than 25 years, and a history of unexplained stillbirths. At 24 to 28 weeks' gestation, a 50-g glucose load is given; 1-hr plasma glucose levels greater than 140 mg/dl constitute a positive screening result. Any patient having a positive test result should then undergo a 2-hr, 100-g OGTT to determine whether GDM is present. See: table

Screen high-risk women at first visit, and screen all women at 24–28 weeks' gestation with 75g oral glucose tolerance test. American Diabetes Association revised Standards of Medical Care, published in Diabetes Care special supplement, January 2011. International Association of Diabetes and Pregnancy Study Groups published in Leary, J. et al. (2010). Best Practice Research Clinical Endocrinology and Metabolism 24 (4), 673.
Time:Glucose level exceeds:
Fasting92 mg/dl
60 min180 mg/dl
120 min155 mg/dl
180 min140 mg/dl
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Taking into account the parameters of insulin resistance (OGTT values, HOMA-IR, and fasting insulin), fasting insulin was the best predictor of the non-responsiveness to clomiphene.
The effect of mode of delivery (vaginal or caesarean section) on OGTT results at 48 to 72 hours, and six weeks postpartum was also assessed.
Simple regression analyses were used to determine the influence of gender and Tanner stage on fasting insulin ([beta]=1.4; p=0.27 and [beta]= -1.2; p=0.14, respectively), HOMA-IR ([beta]=0.11; p=0.71 and [beta]= -0.4; p=0.03, respectively) and 2-hour insulin after an OGTT ([beta]=11; p=0.10 and [beta]=-5.8; p=0.17).
Only 61 (29.1%) practitioners were using an oral glucose tolerance test (OGTT) for screening purposes; these included 50 gram OGTT by 9 (4.29%), 75 gram OGTT by 51 (24.29%) and 100 gram OGTT by 1 (0.5%) respondent.
There are 2 sets of diagnostic criteria recommended for the 2-step process in the US; both are based on the "O'Sullivan criteria" for the 100-g glucose load, 3-h OGTT derived by using 2 standard deviations above the mean for each of the 4 glucose values.
Since the new strategy using 75 g OGTT as one-step screening is still controversial, and the prevalence of GDM varies among different racial groups, together with that it has never been tested in our obstetric population or those in most developing countries, where the people are biophysically different, we conducted this study to evaluate its effectiveness in our population.
The oral glucose tolerance test (OGTT) and IP injection glucose tolerance test (IPIGTT) were performed at two and seven weeks after surgery, respectively.
The diagnosis of active disease was based on the clinical features of acromegaly, failure of GH suppression to below 1 [micro]g/l in response to a 75 g oral glucose tolerance test (OGTT), plasma IGF-1 levels above the age-appropriate reference range, and radiological evidence of a pituitary tumor.