Chemistry Laboratory 6

glucose oxidase procedure
you have to have at least 5 test tubes (blk, L1, L2, Std, and Patient) filled with glucose liquicolor reagent. Then add correct ingredients to the labeled test tube and mix and incubate. Record the absorbances at 500nm then calculate the concentrations of the controls and the patients using beers law.
The sources of error
interfering substances like hemoglobin, uric acid, ascorbic acid, and bilirubin
The reference range of concentration of glucose oxidase
adult are 74-100 mg/dL
The control levels
have predetermined values with reference ranges. They are used to verify accurate test performance.
The principle of the glucose oxidase procedure
glucose oxidase enzyme will convert glucose in to a product, which can be used in another reaction to produce a colored complex. The colored complex can be measure spectrophotometrically and the absorbance is proportional to the amount of glucose in the sample.
The concentration of glucose is calculated by using beer’s law
Cu = Au/As x Cs, Cs is given, answer is in mg/dL
Are the results accurate?
if controls are within range, then yes
Are the results precise?
need to compare run 1 to run 2, are the results similiar
What do you do if the controls are out of range?
trouleshoot the procedure, figure out what went wrong.
What do you do if one of your unknowns is greater than 400 mg/dL
dilute to 1:2 and re-run, remember to multiply results by 2
Glucose levels in spinal fluid are used to diagnose
meningitis
Example of a monosaccharide
glucose
Example of a disaccharide
maltose
Example of a polysaccharide
glycogen
Insulin is produced by
beta cells of the pancreas
During a brief fast, the glycogen stores of the _____ are drawn upon to release glucose
liver
Other than glucose oxidase, name 2 other methods for glucose determination
glucose-1-dehydrogenase and hexokinase
Three pathogenic conditions causing a rise in glucose concentration in the serum
diabetes, hyperthyroidism and cushing’s disease
Three pathogenic conditions causing a decrease in glucose concentration in the serum
tumors, addison’s and hypothyroidism
Adult reference range for plasma or serum
74-100 mg/dL
Adult reference range for whole blood
65-95 mg/dL
Adult reference range for CSF
40-70 mg/dL
Adult reference range for urine
1-15 mg/dL
Blood drawn for glucose determination should be centrifuged within 1 hour due to__________, which ______the glucose level
glycolysis, decreaes
CSF should be analyzed for glucose without delay due to _______, which _________ the glucose level
bacterial contamination, glycolysis and decrease
Why does glycosolated hemoglobin reflect long term control of the diabetic
measurement of the percentage of hemoglobin bound to glucose which is indicative of the amount of glucose over the lifespan of the RBC
A urine specimen for glucose determination should be collected in a ________ medium in order to suppress ____________
acidic, bacterial activity (glycolysis)