testing Flashcards
urinometer
tests SG
add 0.001 for every 3 degress above calibrated temp
subtract 0.001 for every 3 degrees below calibrated temp
subtract 0.003 for each g. of protein
subtract 0.004 for each g. of glucose
refractometer
measures SG; refractive index
calibrated with distilled water 1.000
read line while pointed at light
isosthenuria
same SG 1.010 as plasma filtrate
hyposthenuria
SG <1.010
due to increased hydration, diabetes insipidus
hypersthenuria
SG >1.010
dehydration, diabetes mellitus, IVP dye
pH normal values
4.5-8.0 (see closer to 6-7)
pH indicates
acidosis/ alkalosis
pH test
double indicator: methyl red and bromothymol blue
measures amount of H+
pH test interference
increased bacterial growth increases pH
protein normal values
negative/trace
trace do SSA
protein test type
protein error of indicators
pH @3
albumin accepts H+ === color change
yellow===green===blue (albumin)
protein test interference
false +; detergents, increased pigmented urine
false -: microalbuminuria
clinical significance of protein
nephropathy, injury, toxic agents
prerenal, postrenal, renal, and tubular disorders
protein changes on standing
decrease as break down
SSA
cold ppt. test
reacts w/ all forms of protein
glucose normal values
0
glucose test
glucose oxidase double sequential enzyme reaction
measures glucose
clinical significance of glucose testing
diabetes, inborn error of metabolism, hyperglycemia, glycosuria,
glucose test interference
false +: oxidizing agents (peroxide), detergents
false - : vit C, high ketones, high SG, low temp
clinitest
reacts with all reducing sugars relux for glucose + patients under 2 years old- galactose GALT copper reduction test (exothermic) watch for pass through (-) blue/green==yellow==orange/red (+)
glucose critical levels
3+ & 4+ call the floor
KETONE NORMAL
0
sodium nitroprusside test
measures acetoacetic acid in alkaline medium (purple color)
measures ketones
acetest tablets
measure ketones
sodium nitroprusside with lactose give a better color
clinical significance of ketones
diabetic acidosis, malabsorption, alcoholism, inborn errors of amino acid metabolism, starvation
renal threshold of glucose
160-180 mg/dL
renal threshold of glucose
160-180 mg/dL
ketone test interference
false +: increased pigmented urine, levodopa, meds with sulph grps., phthalein dyes
false - : improper preservation
glucose changes on standing
decrease as bacteria proliferate and use glucose
critical values ketones
4+ call the floor
ketone changes on standing
decrease
blood test normal
negative/ trace
blood test
pseudoperoxidase of Hgb to catalyse reaction btwn heme and chromogen (blue/green color)
clinical significance of blood test
hematuria, myoglobinuria, hemoglobinuria
interference with blood test
false +: oxidizing reagents, bacterial peroxidases, menstral contamination, myoglobin
false - : high SG, crenated cells, formalin, high nitrite, high vit. c
myoglobin precipitation test
ammonium sulfate ppt. hemoglobin and myoglobin stays in supernatant which will be a red color
changes on standing with blood
rbc lyse, increase/decrease depending on time
biliruibin normal levels
negative
bilirubin test
diazo reaction: bilirubin + 2,4 dichloroaniline diazonium salt produces azo dye
tan==pink==violet
bilirubin test clinical significance
hepatitis, cirrhosis, liver disorders, billary obstruction
bilirubin reflux test
ictotest: SSA, p-nitrobenzene diazonium p toulenesulfate
bilirubin stays on surface of the mat
blue==purple (+)
bilirubin test interference
false+: increased pigmented urine, indican
false - : exposure to light, vit c, increased nitrite
bilirubin change on standing
decrease
urobilinogen test normal
negative 0.1-0.2 mg/dL
urobilinogen test
multistix: Ehrlich rxn (urobilinogen reacts with p-dimethylaminobenzaldehyde)
light pink==dark pink (+)
chemstrip: diazo reaction (urobilinogen reacts with 4 methyloxybenzene-diazonium-tetrafluoroborate) *more specific
white==pink
urobilinogen test clinical significance
liver disease, hepatitis, cirrhosis, carcinoma, hemolytic disorders
urobilinogen test interference
false +: porphobilinogen, indican, increased pigmented urine
false - : old specimen, formalin, increased nitrite
urobilinogen change on standing
decrease
watson swartz test
differences btwn urobilinogen, porphobilinogen, and Ehrlich compounds
URO will extract into chloroform/butanol
PORPHO will not extract and stay in urine
Ehrlich will extract into butanol but not chloroform
tube 1: urine, chlorine, sodium acetate
tube 2: urine, butanol, sodium acetate
if both tubes are red all the way through- chloroform tube take top layer and do additional chloroform extraction to test for excess URO
nitrate test normal
negative
nitrate test
greiss reaction: nitrite reacts w/ aromatic amine to prod. diazonium compound which reacts with tetrahydrobenzoquinolin
pink colored azo dye
nothing===pink
clinical significance of nitrite test
UTI, pyelonephritis, AB therapy monitoring, screening urine for culture
nitrite test interference
false +: increased pigmented urine, improper preservation of sample
false - : non reductase bacteria, lack or urinary nitrate, not enough time for bacteria to reduce, increased vit, c, increased SG
antibiotics
nitrite change on standing
increased
leukocyte esterase test normal levels
negative/ trace
LE test
LE catalyzes hydrolysis of acid ester on pad.
Aromatic compound + acid= aromatic + diazonium salt = purple azo dye
nothing==purple
longest test at 2 mins.
LE test clinical significance
UTI, inflammation
LE test interference
false +: oxidizing substances, increased pigmented urine, formalin
false - : increased protein, increased glucose, vit c,
LE changes on standing
no change; long term decrease
Specific gravity test normal levels
1.015-1.025
SG test
pKa change of polyelectrolyte which ionizes releasing H+ in proportion to # of ions in solution
blue==green==yellow
multistix: maleic anhydride
chemstrip; tetraacetic acid
SG test clinical significance
monitor hydration, loss of renal tubular concentration ability, diabetes insipidous
SG test interference
false +: increased protein
false - : highly alkaline urine
SG changes on standing
no significant change