UA- Microscopic

Question 1

What does centrifuging urine do?

Answer 1

separate sediment from liquid
examined for: epithelial cells, RBCs, WBCs, mucus, bacteria, casts, crystals, yeast, artifacts, trichomonas vaginalis, eggs of schitosoma haemotobium & pinworm eggs

Question 2

In a high powered field (HPF) what should you not see?

Answer 2

> 3 erythrocytes
5 leukocytes
2 renal tubular cells
10 bacteria

Question 3

In a low powered field (LPF) what should you not see?

Answer 3

> 3 hyaline casts or >1 granular cast
10 squamous cells
any other cast (RBC, WBC)

Question 4

What should you not see in either?

Answer 4

• fungal hyphae or yeast, parasite, viral inclusions
• pathological crystals
• large # of uric acid or calcium oxalate crystals

Question 5

What are the 3 types of epithelial cells? Where does each come from? What does each look like?

Answer 5

1. squamous- contaminant from lower GU; large, flat, irregular-shaped, ‘fried-egg’
2. transitional- line urinary tract from renal pelvis to proximal 2/3 of urethra (occasionally seen); 2-4x’s larger than leuks, round, pear-shaped, large round nucleus
3. renal- renal tubules, rare cells OK; slightly larger than WBCs, flat, cuboidal or columnar, one large round nucleus

Question 6

What will RBCs look like? WBCs?

Answer 6

RBCs: pale or yellowish w/smooth biconcave disk, no nucleus or cytoplasmic granules, will ‘wink’ at you when refractory changed
WBCs: large, 2x’s size of RBC, often neutrophils so multi-lobed nucleus

Question 7

Where are casts formed and what classifications are there in order for them to form? What are they associated with?

Answer 7

• formed in DCT & collecting tubules
• pH must be acidic & urine concentrated
• associated w/proteinuria & urinary stasis

Question 8

What are hyaline casts? What are they made of? What diseases are they associated with?

Answer 8

• conglomerations of protein; indication of proteinuria
• made of Tamm-horsfall proteins (protein from tubules themselves)
• associated with: glomerulonephritis, pyelonephritis, CHF, CRF (chronic renal failure)

Question 9

Causes of short term proteinuria?

Answer 9

• strenuous exercise
• orthostatic proteinuria
• fever

Question 10

What are RBC casts indicative of?

Answer 10

BLEEDING FROM KIDNEY in association w/reduced urine flow

• glomerulonephritis
• SBE
• renal infarcts, vasculitis, sickle cell anemia
• SLE, malignant hypertension, Goodpasture’s syndrome

Question 11

What are WBC casts indicative of?

Answer 11

INFECTION OR INFLAMMATORY KIDNEY DISEASES

• presence excludes lower urinary tract as source of infection or inflammation
• acute pyleonephritis, glomerulonephritis, lupus nephritis

Question 12

What are renal tubular epithelial cell casts indicative of?

Answer 12

• nephrosis
• amyloidosis
• heavy metal or other poisoning
• glomerulonephritis
• actue tubular necrosis
• pyelonoephritis

Question 13

What are two other categories of casts?

Answer 13

granular= degenerated cellular casts
waxy or ‘broad’= degenerated granular casts, chronic destructive renal diseases, “renal failure casts”
fatty= contain fat, seen in chronic renal diseases, nephrosis, nephrotic syndrome

Question 14

Are crystals always pathologic? What does the type depend on? What can it help diagnose? What do proteus caused UTIs cause?

Answer 14

• not necessarily!
• type depends on pH
• can help diagnose metabolic disease
• UTIs caused by proteus are associated with formation of triple phosphate crystals