Quick Review Cards for Medical Laboratory Science

Chemical Urinalysis by Reagent Stripcontinued

Urinalysis and Body

Fluids Review 491

TEST NORMAL PRINCIPLE SIGNIFICANCE COMMENTS

Bilirubin

Urobilinogen

Nitrite

Leukocyte
esterase

Specific
gravity (SG)

Only conjugated bilirubin is excreted

in urine.

Reagent strips don’t detect absence

of urobilinogen, only ↑.

Some bacteria reduce nitrates to

nitrites. 1st am specimen best.

↑sensitivity when urine in bladder

at least 4 hr.

Longest rxn time. Detects intact &

lysed grans & monos, not lymphs.

Can be used with nitrite to screen

urines for culture.

Only measures ionic solute. Not

affected by urea, glucose, radi-

ographic contrast media, plasma

expanders. Not always same as

SG by refractometer.

Neg

1 Ehrlich unit or 1

mg/dL

Neg

Neg

Random

specimen:

1.003–1.030

Diazo reaction

Ehrlich’s aldehyde rxn or

diazo rxn

Greiss reaction

Leukocyte esterase rxn

pKa change of

polyelectrolyte

Liver disease, biliary

obstruction

Liver disease, hemolytic

disorders

UTI

UTI

Indication of kidney’s

concentrating ability &

state of hydration. ↑in

diabetes mellitus due to

glucose. ↓in diabetes

insipidus due to ↓ADH