Urine testing Flashcards Preview

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Flashcards in Urine testing Deck (15):
1

Glucose/ketones

Detection:
glucose - rxn with glucose oxidase
ketones - nitroprusside rxn detects acetaldehyde and acetone

Gluc elevated when: serum > 10 mmol/L (DM)
Renal tubular resorption defect (renal glycosuria)

Ket elevated in: diabetic ketoacidosis (gluc + ketones in urine), also fasting states

2

Nitrites/WBC

Nitrite elevated: bacteria with nitrate reductase activity (first morning urine best)

WBC present: inflammation - intact & lysed leukocytes have leukocyte esterase

3

Hematuria

Blood detected by: peroxidase-like activity due to Hb
+ indicates: hematuria, hemoglobinria or myoglobinuria
can be false + with elevated ascorbic acid

Causes: hematologic (coagulopathy, sickle cell anemia), renal (glomerular, non-glomerular), post-renal (kidney stones, tumour downstream, cystitis)

4

Proteinuria

Change in osmotic concentration --> change in ionic strength --> colour change in pH in a sensitive dye
Normal <150 mg/day

Causes:
-glomerular
- tubular
-overflow proteniuria

5

Hematuria + proteinuria indicates

glomerulonephritis

6

RBC cast

distinct red cells
glomerular injury, renal bleeding

7

Hyaline cast

non-specific transparent
dehydration, fever, exercise

8

Coarse granular cast

coarse refractile granules
cell degeneration/proteinuria

9

fine granular cast

semitransparent
nonspecific

10

Calcium oxalate

acidic, neutral to slightly alkaline crystal
also can be due to: increased uric acid levels, decreased urinary citrate levels, distal renal tubular acidosis

11

Triple phosphate - urine

AKA struvite stones
Ammonium magnesium phosphate
Some bacteria are able to split urea --> ammonia, increase urine pH
Reduce solubility of magnesium ammonium & phosphate
Alkaline urine
UTI (Proteus, Klebsiella, Pseudomonas)
Staghorn calculi

12

Uric acid crystals

Acidic urinary pH (Diarrhea)
Dehydration
Uricosuric drug (salicylates, thiazides)
high protein diet
increased serum uric acid levels (gout, leukemia, chemotherapy)

13

Cysteine in urine

Cystinuria
Inherited defect in renal tubular resorption of cysteine, ornithine, lysine, arginine
acidic urine
hexagonal crystals

14

RBC in urine

Usually <3 /hpf
trauma, malignancy, cystitis, infections, prostatitis
Dysmorphic RBCs: RBC of glomerular/renal origin
- damaged during gromerular/tubular passage

15

WBC in urine

Usually <1 / hpf
UTI, inflammation