Urinalysis Flashcards
What 10 things does a dipstick look at?
pH Specific gravity Blood Protein Glucose Ketones Nitrite Leukocyte esterase Bilirubin Urobilinogen
Normal urine pH
4.5 to 8
Specific gravity
Ratio of the density of urine to the density of an equal volume of distilled water
Provides information on kidneys’ concentrating ability
What 2 things make a dipstick positive for blood?
Hemoglobin and myoglobin
2 reasons why glucose may be present in urine
Filtered glucose load exceeds the reabsorptive capacity of the renal tubules (ex: DM)
Defect in reabsorption of filtered glucose (ex: Fanconi syndrome)
Leukocyte esterase
Enzyme found in neutrophils and macrophages
Positive test indicates the presence of intact or lysed WBCs (infection, inflammation, malignancy, stones, GN)
4 things microscopic analysis of the urine looks at
Casts
Crystals
Cells
Organisms
What are some things that can cause RBCs in urine
Vigorous exercise Trauma Stones Infections Urinary tract malignancies Glomerular disease
Renal tubular epithelial cells
Variable shape depending on the tubular segment of origin
All have a well-defined round or oval nucleus
Increased with renal tubular damage (ATN, AIN, GN, acute cellular rejection of kidney allograft)
Oval fat bodies
Renal tubular epithelial cells or macrophages that are packed with lipid droplets
Lipid droplets have a characteristic “Maltese cross” appearance under polarized light
Seen in nephrotic syndrome and lipid storage disorders
Free lipid droplets
Seen in nephrotic syndrome, major trauma with fat emboli, lipid storage disorders, or as a contaminant
What are urinary casts
“Imprints” formed in the distal convoluted tubular/CT of the nephron
Snapshot of what is occuring in the tubules at the time of formation
Composed of mucoproteins and trapped elements
Urinary stasis, concentrated ultrafiltrate, presence of excess proteins, and acidic pH all favour cast formation
Broad casts
Wide casts formed in diluted renal tubules
Indicate advanced CKD
Urinary crystals
Formed when urine is supersaturated with chemical constituents
Common
Usually of little/no clinical importance
4 factors affecting crystal formation
Concentration of constituents
Hydration status
Temperature
pH
