Body Fluids Midterm: Chemical Evaluation

glucose

Peroxidase catalyzes the reaction between peroxide and chromogen to form the color the is proportional to the concentration of _______________

Glucose oxidase reaction

What is the basis for urine strip glucose reaction

residual detergents in collection container

What causes false positive results on a dipstick glucose

false decrease

ascorbic acid, high ketone levels, and low temperature can cause a false increase/decrease of dipstick glucose reaction

diazo reaction

What is the principle of the bilirubin dipstick reaction

bilirubin

Old specimen, ascorbic acid > 25 mg/dL, and nitrites can cause a false negative reaction with what dipstick analyte?

True

The kidneys cannot excrete unconjugated bilirubin. True/False

bile duct obstruction or liver damage

What conditions are associated with a high bilirubin levels in urine?

sodium nitroprusside

What is the primary reagent involved in ketone determination on a urine dipstick

acetoacetic acid

What is the primary ketone measured on the dipstick

Beta - hydroxybutyrate blood test

What is the best indicator of ketone measurement

false negative ketone reaction

The breakdown of acetoacetic acid from bacterial overgrowth in a urine is a concern for what reason

concentration (specific gravity)

A polyelectrolyte releases hydrogen ions in relation to the _____________________________ of urine in this dipstick test

bromthymol blue

What is the indicator used for dipstick specific gravity

decrease

pH of 6.5 or higher might do what to specific gravity measurement on the urine dipstick

False. This test will detect hemoglobin and myoglobin

Pseudoperoxidase activity is specific for hemoglobin detection on a urine dipstick. True/False

pseudoperoxidase

What enzyme catalyses the reaction which detects blood on a urine dipstick

blood

tetramethylbenzidine is the chromogen used for what dipstick analyte

hemoglobin from myoglobin (causes hemoglobin to precipitate out)

The ammonium sulfate test differentiates what two analytes?

double indicator system reaction

What is the basis of the pH determination on a urine dipstick?

4-6

Methyl red determines a pH of _____ - _____

6-8

Bromothymol blue determines a pH of ____-____

protein

What dipstick analyte is detected through the error of indicators

highly buffered alkaline urine

What is a source of interference in protein detection on a urine dipstick

Ehrlich's reagent

p-dimethylaminobenzaldehyde is also known as....

urobilinogen

The Ehrlich's aldehyde reaction is used for what dipstick analyte

-bilirubin decreased

-urobilinogen increased

Hemolytic anemias would cause what to happen to bilirubin and urobilinogen levels in urine

Nitrite

Which dipstick analyte utilizes the Greiss reaction

nitrite (Greiss Reaction)

The formation of a diazonium salt which reacts with tetrahydrobenzoquinoline to form a pink azodye is is the basis for what analyte detection on the dipstick

-bacteria that do not reduce nitrate

-insufficient time for bacteria to make convert the nitrate

-bacteria that are able to convert nitrite to nitrogen

-lack of nitrate in the urine for conversion

-antibiotics

What are five reason nitrite might be negative in the presence of bacterial infection

Leukocyte esterase

What catalyzes a reaction that creates an aromatic compound and an acid which reacts with diazonium salt to produce a purple color

leukocyte esterase

Which analyte typically takes longer to react, and may produce false negatives if read before 2 minutes

SSA

confirmatory test for protein

Clinitest

Copper reduction test AKA

clinitest

Test used to detect galactose in the urine of infants

ictotest

Tablets containing p-nitrobenzene-diazonium-p-toluenesulfonate, SSA, sodium carbonate, and boric acid are used in what confirmatory test

supravital stain (Sternheimer and Malbin)

What is the most common stain used for urine sediment visualization (microscopy)

5 mins at lo speed (1500-2000 RPM)

Describe the centrifuge parameters for spinning urine

first morning void due to high concentration

Which urine specimen is most likely to demonstrate abnormal chemistry results

-first urine upon waking

-before consuming any foods or liquids

-no food/liquid overnight

What are the conditions required for collecting a first morning void

Vitamin C supplement usage

Why might high levels of ascorbic acid be found in the urine of patients?

-glucose

-blood

-bilirubin

-nitrite

-leukocyte esterase

What 5 analytes on a dipstick might give unreliable results in the presence of ascorbic acid?

glucose is oxidized to gluconic acid and hydrogen peroxide by glucose oxidase

What is the first step of the enzymatic reaction for dipstick glucose detection

peroxidase catalyzes a reaction between hydrogen peroxide and a chromagen to develop a green dye

What is the second step of the enzymatic reaction for dipstick glucose detection

ketone

What dipstick analyte is detected on the principal of the Legal's test?

specific gravity

the ratio of the density of the substances being measured to the density of pure water is called _________________ ______________________

5-7

What is the normal range of urine pH?

ascorbic acid

what may cause a false positive reaction on the clinitest

-Urine has a strong color that masks results

-urine has a strong alkaline pH that results in false positive

What reasons would cause you to use an SSA test for proteins in urine?

equal parts SSA and spun urine supernatant

How would you prepare an SSA test

True

The ictotest is more sensitive that the dipstick for the detection of bilirubin. True/False

refractive index

A ratio of the velocity of light in air and the velocity of light in solution

specific gravity

The refractive index correlates with which property of urine