2.11: Glucose Tolerance Test
- Page ID
- 120228
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)
RELATED READING: Chapter 32. See Methods in CD-ROM for Glucose.
OBJECTIVES
Upon completion of this exercise, appropriate discussion, and related reading, the student will be able to:
- Explain how to perform a Glucose Tolerance Test (GTT) for Gestational Diabetes.
- Construct a graph showing the relationship of time to serum glucose concentration.
- Perform calculations that allow evaluation of a glucose tolerance test.
- Discuss the possible physiological status of the patient that would produce the observed results.
- Determine urine glucose concentrations (Optional).
PROCEDURE
- Perform glucose determinations on the patient samples provided using the procedure given in the previous exercise (#10). Each student will have GTT samples from one patient drawn at the following intervals: fasting, 60 min., 120 min., 180 min. The determination of urine glucose levels is an optional activity. Your instructor will give you specific instructions dealing with that procedure.
- Perform glucose determinations on the urine samples provided with your GTT samples and record the results on the data sheet (optional).
- Plot the results of serum glucose (mg/L, Y or vertical axis) vs. time (hours, X or horizontal axis) to establish a Glucose Tolerance Curve. Using the discussion of the O’Sullivan-Mahan test (as modified by Carpenter-Coustan) in Chapter 32 determine if the patient has gestational diabetes. The test uses a 100-g glucose load. Cut-off criteria for a normal response to this test are: fasting 950 mg/L, 1-hour 1800 mg/L, 2-hour 1550 mg/L, 3-hour 1400 mg/L. Two or more of the plasma glucose values must be equaled or exceeded for a diagnosis of gestational diabetes.
DATA SHEET, EXERCISE #11 |
NAME: ___________ DATE: ___________ |
Absorb. 525 nm | Calculated Glucose Value (mg/L) | Target Glucose Value (mg/L) | Urine Glucose (Optional) (mg/L) | Exceeds limits? | |
---|---|---|---|---|---|
Standard | |||||
Normal Control | |||||
Abnormal Control | |||||
Fasting | |||||
1 Hr. | |||||
2 Hr. | |||||
3 Hr. |
Discussion Questions
- What do the results of your glucose values, the O’Sullivan-Mahan test and graph suggest regarding this patient?
- Do the urine glucose values you obtained correspond to the serum values in the expected manner? Explain.
- What are the advantages and disadvantages of using a 3 hr. post-prandial evaluation instead of a 4 or 5 hour tolerance test?