Urinalysis Flashcards
Primary organic component. Product of protein and amino acid metabolism
Urea
Product of creatine metabolism by muscles
Creatinine
Product of nucleic acid breakdown in food and cells
Uric acid
Primary inorganic component. Found in combination with sodium and with many inorganic substances
Chloride
Primarily from salt, varies by intake
Sodium
Combines with sodium to buffer the blood
Phosphate
Regulates blood and tissue fluid acidity
Ammonium
It determine if fluid is urine
Urea and creatinine
Average daily urine output
1200mL to 1500mL
Decrease in urine output
Oliguria
Cessation of urine flow
Anuria
Increase excretion of urine at night
Ncturia
Increase in daily urine volume and is associated with diabetes mellitus and diabetes insipidus
Polyuria
>2.5L/day in adults
>2.5 to 3mL/hr in children
A patient presenting with polyuria,nocturia, polydipsia and low specific gravity is exhibiting symptoms of:
Diabetes insipidus
Why is it possible to estimate the concentration of a normal urine specimen by its color?
Urochrome is produced and excreted at a constant rate, so its concentration is affected by the amount of water present in the urine
State a pathologic cause of yellow urine in foam and of white urine foam
Yellow foam: bilirubin
White foam: protein
How does the presence of phenazopyridine affect routine urinalysis testing?
The thick yellow-orange pigment in phenazopyridine masks reagent strip color reactions
What is the significance of a cloudy, red urine?
The urine contains increased RBC’s
Why is there a difference in the color of the serum from person with hemoglobinuria and myoglobinuria?
Myoglobin is more rapidly cleared from the plasma than is hemoglobin
Under what conditions will a port wine urine color be observed in a urine specimen?
Urine containing porphyrins that has been exposed to air.
Why might a brown/black urine have a positive chemical test result for blood?
The specimen containing hemoglobin that has been oxidized to methemoglobin. This may be seen in old specimen or in fresh specimen as a result of glomerular bleeding.
State the conditions required for urines containing melanin or homogentisic acid to appear brown/black
Oxidation of melanogen to melanin produces a black urine; homogentisic acid turns black in alkaline urine.
Name a pathologic cause and a nonpathologic cause of blue/green urine
Urinary and intestinal tract infections may produce blue or green urine. Breath deodorizers (clorets), methocarbamol (robaxin), amitriptyline (elavil), and methylene blue may produce blue or green urine.
Differentiate between the appearance of amorphous urates and urates in a refrigerated urine specimen. What chemical test is critical to the differentiation?
Amorphous phosphates produce a white precipitate and amorphous urates produce a pink precipitates; the precipitation is pH dependent
In what circumstances might a sediment be slightly warmed prior to microscopic examination?
To dissolve amorphous urates
How will collection of a urine specimen using the midstream clean catch method affect the urine clarity?
The specimen will contain fewer contaminating structures and clarity will better represent the actual urine.
When should a microscopic examination be performed on a clear urine specimen?
When a chemical test for protein, RBC’s, or WBC’s or bacteria is positive
For what part of the routine urinalysis does specimen clarity serve as a method of quality control?
Microscopic
Define specific gravity
The density of a solution compared with the density of a similar volume of distilled water
Can a cloudy urine specimen have a low specific gravity? Why or Why not?
Yes, because substances not dissolved in the urine do not contribute to the specific gravity
How can specific gravity be used to determine the quality of a specimen for urinalysis?
Significant pathologic constituents may not be detected in a dilute specimen
Why is specific gravity of less value than osmolarity in evaluating renal concentration ability?
Specific gravity is influenced by the size of the molecules, such as urea, glucose, and protein that are not significant in renal concentration.
