To Perform Glucose Tolerance Test
15
The ability of a person to metabolize a given glucose is called glucose tolerance. To
assess carbohydrate metabolism status, an oral glucose test is employed. Glucose
tolerance test (GTT) is highly useful to confirm diabetes mellitus.
15.1 Method of Carrying GTT............................
The test is usually carried out in the morning. Patient should be on 8–12 h fasting
before undergoing test and should not eat during test. Patient is given glucose
solution (75 g) and is asked to drink it within 15 min. For children 1.75 g glucose/
kg body weight is given. Blood for estimation of glucose is taken at half-hourly
intervals for 2.5 h after the glucose intake. Fasting and every half-hourly urine
specimens are also collected from the patient (six urine samples). Blood glucose
concentration is estimated by GOD method. Urine sugar is detected by Benedict’s
qualitative test.
15.2 Specimen Requirements
Serum/plasma sample is used. For oral GTT, draw fasting sample and then at 30, 60,
90, and 120 min after glucose intake. In case of pregnancy, draw samples at fasting
and at 60, 120, and 180 min after glucose intake.
#Springer Nature Singapore Pte Ltd. 2018
V. Kumar, K. D. Gill,Basic Concepts in Clinical Biochemistry: A Practical Guide,
https://doi.org/10.1007/978-981-10-8186-6_15
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