Urinalysis: Visual, Dipsticks, and Microscopy Flashcards
AR inherited condition in which a BCKDC deficiency leads to a buildup of BCAAs (leucine, isoleucine, and valine) and their toxic byproducts (ketoacids) in the blood and urine unless dietary intake is carefully managed
Maple-syrup-urine syndrome
Long known for its pungent effects on the urine, approximately 25% of the population reports having pungent pee after eating this due to the breakdown of its sulfurous amino acids into volatile/odorous compounds. Interestingly, this breakdown happens in all people so everybody’s urine stinks, but only a fraction of the population expresses the gene needed to smell it
asparagus
In ancient times this disease was diagnosed based on the sweet smell and taste of a person’s urine, while others would pour it in the sand and see if it attracted ants
diabetes mellitus
Having a urinary tract infection and/or kidney stones can impart this smell to urine in part due to breakdown of protein by bacteria
ammonia
A patient has very foamy urine suggesting the presence of protein. The urine dipstick is negative, but a sulfasalicylic acid test does indicate the presence of protein. The protein in this instance is referred to as “Bence-Jones” protein. This finding is a classic (i.e., Step 1) means of illustrating this disorder
multiple myeloma
A urine dipstick specific gravity of 1.025 (on a scale of 1.000-1.030) indicates what?
Urine is highly concentrated
What is likely indicated by a urine pH of 6?
A. Pt has diabetic ketoacidosis B. Pt has respiratory acidosis C. Bicarb is being lost in urine D. Fixed acid is being excreted as ammonium E. The pt has been vomiting F. Pt has been hyperventilating
D. Fixed acid is being excreted as ammonium
What does a negative reading for urine dipstick leukocytes indicate?
A. There’s only eosinophils in the urine
B. The urine bacteria have consumed the leukocytes
C. The pt has infection w/o inflammation
D. A high-power field likely has 3-5 neutrophils
D. A high-power field likely has 3-5 neutrophils
On urine dipstick blood/Hgb analysis: what is suggested if the urine is brown, the dipstick is positive for blood, but there’s no RBCs visible by microscopy?
A. Myoglobinuria B. Intravascular hemolysis C. Urine contains a dye D. Nephrotic syndrome E. Nephritic syndrome F. Analgesic nephropathy
A. Myoglobinuria
What is indicated by a positive nitrite test in urine?
A. Urine contains urea
B. Urine contains uric acid
C. Urine contains creatinine
D. Urine contains a gram negative organism
D. Urine contains a gram negative organism
[positive nitrite associated with E.coli, Klebsiella, Proteus, Enterobacter, Citrobacter, and Pseudomonas]
Note that negative result does not rule out UTI, because some bacteria that cause UTI are incapable of nitrate—>nitrite conversion (like Staph, Strep, and Haemophilus)
What is suggested by a result of 50 mg/dL on urine dipstick analysis for ketones?
A. Pt is consuming a low fat diet B. Pt has nephrogenic diabetes insipidus C. Pt has diabetic ketoacidosis D. Pt likely has hypoglycemia E. Pt is an alcoholic F. Pt has gouty nephropathy
C. Pt has diabetic ketoacidosis
[ketonuria may be seen with uncontrolled diabetes, diabetic ketoacidosis, severe exercise, starvation, vomiting, and pregnancy]
What is indicated by the presence of bilirubin in the urine?
A. Glomerular filtration barriers are compromised B. Disseminated intravascular congestion C. Pt has liver disease D. Pt has iron deficiency E. Pt is constipated
C. Pt has liver disease
[other causes of bilirubin in the urine: obstructive hepatobiliary conditions; liver diseases include hepatitis]
What is suggested by a urobilinogen level of 4 mg/dL on urine dipstick analysis if all other values are within normal limits?
A. High protein diet B. Rhabdomyolysis C. Biliary tract obstruction D. GI superinfection with C.diff E. Hemolytic disease
E. Hemolytic disease
[increased urobilirubin levels are associated with excessive hemolysis, liver parenchymal diseases, constipation, and intestinal bacterial overgrowth]
Note that DECREASED urobilirubin levels would indicate obstructive biliary disease or severe cholestasis
What is likely when pt has 1000 mg/dL of protein in the urine?
A. Nephritic syndrome B. Nephrotic syndrome C. Liver protein production is greater than PCT reabsorptive capacity D. Post-strep glomerulonephritis E. High protein diet
B. Nephrotic syndrome
What does a urine dipstick of 100 mg/dL glucose indicate?
A. Pt has type II DM
B. Pt has central diabetes insipidus
C. Filtered load of glucose is greater than PCT reabsorptive capacity
D. Excess glucose is being secreted by DT
E. Glomerular filtration barrier has been compromised
C. Filtered load of glucose is greater than PCT reabsorptive capacity
[glucose in the urine most commonly indicates diabetes mellitus but can also be seen in pregnancy]
What type of crystals are found in the urine of animals/humans infected with ammonia-producing organisms?
Triple phosphate crystals (struvite)
2 types:
Common form = “coffin lid”
Rapidly precipitated form
Are struvite crystals primarily found in alkaline or acidic urine?
Alkaline
What types of crystals/urinary sediment are found chiefly in alkaline urine?
Ammonium urate Struvite Calcium phosphate Amorphous phosphates Calcium carbonate
What type of crystals/sediment are found chiefly in acidic urine?
Uric acid (football shape) Sodium urate Calcium oxalate (envelope shape) Sulfonamide Amorphous urates Leucine Tyrosine (fine delicate needles) Cystine (hexagon shape)
Cystine, tyrosine, and leucine are among the abnormal crystals of _____ origin
Metabolic
Urinary casts form via precipitation of the ______ mucoprotein secreted by distal nephron cells, the function of which is not fully understood
Tamm-Horsfall
What does it mean to see RBC containing casts in the urine?
There is damage to glomerular endothelial cells
What does it mean to see epithelial casts in the urine?
Epithelial casts form when tubule cells die and slough off
What does it mean to see WBC casts in the urine?
WBC casts form when there is tubulointerstitial nephritis
Blue urine causes
Methylene blue dye (common in some medications, e.g., Viagra), indomethacin, amitryptiline, triamterene, cimetidine (IV), promethazine (IV)
Blue diaper syndrome = tryptophan malabsorption
What vitamin tends to give urine a bright/fluorescent yellow color?
Riboflavin (B2)
What might red urine indicate?
Food — beets, blackberries, rhubarb
Drugs — propofol, chlorpromazine, thioridazine, ex-lax
UTIs, nephrolithiasis, hemoglobinuria (rhabdomyolysis), porphyrias
Causes of orange urine
Carrots, Vit C
Drugs — rifampin, phenazopyridine
Green urine causes
Asparagus
Drugs — vitamin B, methylene blue, propofol, amitriptyline
UTIs
Cause of purple urine
Bacteriuria in pts with urinary catheters (purple urine bag syndrome)
Brown urine causes
Fava beans
Drugs — levodopa, metronidazole, nitrofurantoin, primaquine, chloroquine, methocarbamol, senna
Medical conditions — Gilbert syndrome, tyrosinemia, hepatobiliary dz
Black urine causes
Alkaptonuria
Malignant melanoma
White urine causes
Propofol
Chyluria, pyuria, phosphate crystals
The urinary dipstick only detects the presence of _____ and no other proteins
Albumin
Thus it is very specific, but not a sensitive test for proteinuria — this is especially important to note in pts with diabetes because the urine dipstick is insensitive for microalbuminuria
Also important to note that urine concentration may alter results!
Because the urinary dipstick protein results can be inaccurate, a more accurate test is the _____
Sulfosalicylic acid test (SSA) — detects all proteins in the urine at any amounts, including albumin, globulin, and Bence Jones proteins
What type of urinary casts may be seen in healthy individuals?
Hyaline casts [may be increased after strenuous exercise or with diuretic therapy]
Red cell casts are nearly diagnostic of _____ or _____
Glomerulonephritis or vasculitis
White cell casts and pyuria are most commonly seen with _____ and _____
Tubulointerstitial nephritis
Acute pyelonephritis
[WBC casts are also seen with renal tuberculosis and vaginal infections]
Muddy brown granular casts are diagnostic of what?
Acute tubular necrosis
Waxy and broad casts are consistent with ____
Advanced renal failure
Fatty casts and lipiduria, with typical “maltese-cross” appearance on polarized microscopy, are commonly seen with _____ syndrome
Nephrotic
Calcium oxalate crystals and AKI is seen with ____ ingestion
Ethylene glycol
The presence of large amounts of uric acid crystals and AKI is seen with ____ _____ syndrome
Tumor lysis
[may also be seen with gout]
