Urinalysis Flashcards
What determines specific gravity of a solution?
• when is this a good estimate of osmolality?
Number and Weight of Solutes in a solution
Osmolality:
• This is a good measure of osmolality ONLY when there is not an abnormal number of HEAVY solutes in the solution, for example Radiocontrast
What specific gravity corresponds to isosthenuria, max dilute urine, and max concentrated urine?
Isosthenuria - 1.010 corresponds to ~300 mosm/L
Max. Conc. - 1.030 corresponds to ~1200 mosm/L
Max Dilute - 1.002 corresponds to ~50-100 mosm/L
What is urinary pH a reflection of?
- Dietary Intake
* Adequacy of Acid Base System in Kidney
What are some probable causes for having urine at the following pH values?
• less than 5.3
• 5.4 - 6.5
• Greater than 7.5 or 8.0
Less than 5.3:
• Metabolic Acidosis
Between 5.4 and 6.5:
• Normal
Greater than 7.5 or 8.0:
• Urease Splitting bacteria in UTI
What is suggested by glycosuria at normal blood glucose?
Fanconi’s syndrome
A urine dipstick positive for acetone or acetoacetate may be indicative of what conditions?
This just means you’re using fat for fuel
- Fasting
- Diabetic Ketoacidosis
- Alcoholic Ketoacidosis
T or F: A positive Nitrite Dipstick is suggestive of UTI with gram + rods.
False, Urease containing bacteria are usually gram -
What does a positive leukocyte esterase tell you?
• what is this specific for?
• Means there are neutrophils in the urine
This is not a specific test, IT JUST INDICATES the presence of WBCs which could also be present in other inflammatory conditions besides just inflammation
How is quantitative Proteinuria detected?
• semiquantitative?
Quantitative:
• 24 hour urine collection
• Spot creatinine is also fairly accurate
Semi-Quantitative:
• Urine Dipstick
Note: some proteinuria is normal… ~150 mg/day are excreted… much of it is Tamm-Horsfall
What dipstick rankings tell you that its Nephrotic Range Proteinuria?
• what protein is detected?
3+ to 4+ = normal proteinuria
Albumin = only protein detected by urine dipstick
to detect all proteins you must use Sulfosialicylic Acid test
What causes tubular proteinuria?
PROXIMAL Tubules are responsible for reabsorbing most of the protein that gets through the glomerulus via Pinocytosis
- FAILURE TO REABSORB HERE IS PROXIMAL TUBULE DYSFUNCTION
- if this doesn’t happen you’ll get a mild proteinuria
What key combination of tests for proteinuria tell you that someone has multiple Myeloma?
- Negative Urine Dipstick
- Positive Sulfosialicylic Acid Test
this is light chain proteinuria
What does a positive and negative urinary Anion Gap tell you?
UAG: (Na+K) - Cl-
Positive Urinary Anion Gap:
• tells you that its a RENAL issue - because there should be greater NH4+ secretion during acidosis which MUST BE SECRETED WITH Cl-
Negative Urinary Anion Gap:
• tells you that its a GI issue - Cl- is increased to balance NH4+ that is excreted in the urine, since NH4+ is not in the calculation, you get a NEGATVIE UAG
What is the most common cause of a positive urinary dipstick for blood: Free Hemoglobin/myoglobin or RBCs?
RBCs 0-2 are typically seen, most often this is in a menstruating female
Lesson: RBCs in urine is not always a kidney issue, could be UTI or physiologic (menstrual)
What are some key characterisitics to look for to determine if blood in the urine is of renal or non-renal origin?
Renal: • DYSMORPHIA in RBCs • RBC Casts present • NO clots should be present • Associated with Proteinuria
RBCs will look normal, there won’t be casts, and proteinuria will NOT be present in non-renal issues, there might also be clots
