C5 Glucose through Ketones Flashcards
The most frequent chemical analysis performed on urine?
glucose
clinical significance of glucose:
major screening test for DM, renal threshold is 160-180 mg/dl, higher blood sugar
disease state when placental hormones block action of insulin?
gestational diabetes
hormonal disorders
pancreatitis, pancreatic cancer, acromegaly, Cushing’s syndrome, hyperthyroidism, pheochromocytoma
Hormones
glucagon, epinephrine, cortisol, thyroxine, growth hormone oppose glucose
Insulin
converts glucose to storage glycogen
hormones
glycogen back to glucose
epinephrine
inhibits insulin; seen with stress, cerebral trauma, and MI
Renal glycosuria
tubular reabsorption disorder, end-stage renal disease, Fanconi syndrome, cystinosis
Reagent strip: chromogens used:
potassium iodide (green to brown) & tetramethylbenzidine (yellow to green)
Reaction interferance: false positive
only peroxide, oxidizing detergents
Reaction interference: false negative
enzymatic reaction interferance ((ascorbic acid and strong reducing agents))
Copper Reduction Test (Clinitest)
reduction of copper sulfate to cuprous oxide with alkali & heat, color change- negative blue (CuSO4) through green, yellow, and orange/red (Cu2O)
CuSO4(cupric sulfide)+reducing substance=
heat
CuSO4(cupric sulfide)+oxidized substance+color
alkali
In a clinitest, hygroscopic tablets: strong blue color and excess fizzing=
deterioration
Interferance from reducing sugars:
galactose, lactose, fructose, maltose, pentoses, ascorbic acid, cephalosporins
What is the major use for the clinitest?
inborn error of metabolism, in children up to 2 yrs, not specific for glucose
Ketones
3 intermediate products of fat metabolism: acetone: 2%, acetoacetic acid: 20%, B-hydroxybutyrate: 78%
diabetic ketoacidosis
increased accumulation of ketones in the blood (electrolyte imbalance, dehydration, & diabetic coma)
Reagent Strip, primary reagent
sodium nitroprusside
Acetest
not a urine confirmatory test, tablet=sodium nitorprusside, glycine, disodium phosphate, lactose…. test for ketones