Reference no: EM132298818
Biomolecules & Life Processes Assignment - Data Analysis and Biomedical Problem Solving
Background - The Oral Glucose Tolerance Test (OGTT) is a biomedical test in which a glucose load is administered and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is used for diagnosis of the major types of diabetes (Type I and Type II), and sometimes reactive hypoglycemia and acromegaly, or rarer endocrinological disorders of carbohydrate metabolism. The most commonly performed version of the test takes an initial blood sample after an overnight fast and the baseline blood glucose level (the fasting value) is determined. Then a standard dose of glucose is ingested by mouth and blood levels are checked two hours later (the 2 hour value). The fasting and 2 hour blood glucose values are used as the diagnostic levels for determining either the absence of diabetes or the presence of diabetes or prediabetes.
Standard Oral Glucose Tolerance Test (OGTT)
Preparation - Usually the OGTT is performed in the morning after an overnight fast as glucose tolerance can exhibit a diurnal rhythm with a significant decrease in the afternoon. The patient is instructed to fast (water is allowed) for 8-12 hours (e.g., overnight) prior to the tests.
Procedure -
1. A zero time (baseline) blood sample is taken at the start of the test.
2. The patient is then given a measured dose of glucose solution (75 g oral dose in all adults) to drink within a 5 minute time frame.
3. Blood is drawn at intervals for measurement of glucose (blood sugar), and sometimes insulin levels. The intervals and number of samples vary according to the purpose of the test. For simple diabetes screening, the most important sample is the 2 hour sample and the 0 hour and 2 hour samples may be the only ones collected. Blood samples may be taken at the 1 hour point and blood samples may continue to be collected for up to 6 hours depending on the protocol requested by the physician.
Interpretation of OGTT results -
- Normal fasting plasma glucose (measured at the start of the OGTT before the glucose load is administered) should be below 6.1 mmol/L.
- Fasting levels between 6.1 mmol/L and 7.0 mmol/L are borderline ("impaired fasting glycemia"), and fasting levels repeatedly at or above 7.0 mmol/L are diagnostic of diabetes.
- A 2 hour OGTT glucose level below 7.8 mmol/L is normal, whereas higher glucose levels indicate hyperglycemia.
- A 2 hour OGTT glucose level between 7.8 mmol/L à 11.1 mmol/L indicates "impaired glucose tolerance".
- A 2 hour OGTT glucose level above 11.1 mmol/L confirms a diagnosis of diabetes.
Patient Case Study -
Diabetes is a group of complex metabolic diseases exemplified by high blood glucose levels over a prolonged period. Diabetes requires daily self care and if complications develop, diabetes can have a significant impact on quality of life and can reduce life expectancy. Diabetes is due to either the pancreas not producing enough insulin or the cells of the body not responding properly to the insulin produced.
There are three main types of diabetes:
- Type 1 diabetes (T1D) results from the pancreas's failure to produce enough insulin. This occurs because the pancreatic β cells that produce insulin are destroyed. The exact reasons for the loss of pancreatic β cells remain unknown. This form of diabetes was previously referred to as insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes.
- Type 2 diabetes (T2D) begins with insulin resistance, a condition in which cells fail to respond to insulin properly. As the disease progresses a lack of insulin may also develop. This form was previously referred to as non insulindependent diabetes mellitus (NIDDM) or adult-onset diabetes. The primary causes of T2D are excessive body weight and not enough exercise.
- Gestational diabetes occurs when pregnant women without a previous history of diabetes develop high blood glucose levels.
Patient Case Study -
Larry
- Male; 53 years of age
- Body mass index (BMI) 31.4 kg/m2
- Hypercholesterolemia
- Patients mother has type 2 diabetes
- Urine Ketostix Test = negative
Curly
- Male; 36 years of age
- Body mass index (BMI) 24.8 kg/m2
- No family history of diabetes
- Urine Ketostix Test = negative
Moe
- Male; 17 years of age
- body mass index (BMI) 21.3 kg/m2
- No family history of diabetes
- Urine Ketostix Test = positive; moderate result 1.6 - 3 mmol/L
Data Analysis and Interpretation -
1) Plot a standard calibration graph for the glucose assay. This graph will be Figure 1.
NOTE: Think carefully about which variable is plotted on the x-axis and which is plotted on the y-axis.
REMEMBER: the independent variable is plotted on the x-axis and the dependent variable is plotted in the y-axis.
- Give your figure an appropriate title.
- Label the x-axis and y-axis.
- Include the appropriate units for each labelled axis.
- Note of advice: If using Excel to plot your calibration graph, choose a marked scatter plot and add a line of best fit.
2) Using your calibration graph determine the glucose concentrations (mmol/L) for all the patient samples.
Remember you will need to correct for dilutions and convert the [glucose] from mg/mL → mmol/L.
Complete Table 3 by adding in your calculated patient glucose concentrations (mmol/L).
Answers should be rounded to two (2) decimal places.
3) Plot a second graph detailing the changes in patient blood glucose concentrations against time. The blood glucose concentrations (mmol/L) will be on the y-axis and the three time points on the x-axis will be: Fasting value = 0 hours; 1 hour value = 1 hour; 2 hour value = 2 hours.
This graph will be Figure 2.
- Give your figure an appropriate title.
- Label the x-axis and y-axis.
- Include the appropriate units for each labelled axis.
- On the graph use different symbols and/or coloured lines to differentiate between each patient.
- Provide an informative key for identification of the 3 patients.
- Note of advice: If using Excel to plot this graph, choose either a marked line plot or a straight marked scatter plot. Do not use a smooth marked scatter plot.
4) Give a brief interpretation of the OGTT results for each patient (Larry, Curly, Moe).
Comment on their potential diagnosis on the basis of their calculated and documented OGTT results, as well as using the additional information given.
Provide biomedical reasoning to support your statements.
Attachment:- Assignment File.rar