Microscopic

Question 1

What is the purpose of microscopic examination of urine?

Answer 1

To detect and identify insoluble materials in urine

Question 2

When should microscopic examination be performed?

Answer 2

When requested by a physician or when abnormal physical/chemical results are obtained

Question 3

Which urine elements degrade quickly in alkaline urine?

Answer 3

RBCs, WBCs, and hyaline casts

Question 4

What can refrigeration cause in urine specimens?

Answer 4

Precipitation of amorphous urates and phosphates

Question 5

What is the recommended specimen volume for urine microscopy?

Answer 5

10-15 mL (commonly 12 mL)

Question 6

How is centrifugation calibrated?

Answer 6

By calculating Relative Centrifugal Force (RCF)

Question 7

What is the formula for RCF?

Answer 7

RCF = 1.118 × 10⁻⁵ × radius in cm × RPM²

Question 8

How long and at what speed should urine be centrifuged?

Answer 8

5 minutes at 400 RCF

Question 9

Why should centrifugation tubes be capped?

Answer 9

To prevent biohazardous aerosols

Question 10

What is the sediment concentration factor?

Answer 10

Volume of urine centrifuged ÷ sediment volume

Question 11

How should urine sediment be prepared before examination?

Answer 11

Aspirated off, gently resuspended to prevent cell disruption

Question 12

What volume of sediment is examined in the conventional glass-slide method?

Answer 12

20 µL (0.02 mL) covered by a 22 × 22 mm glass coverslip

Question 13

Why is urine sediment first examined under low power (10x)?

Answer 13

To detect casts and general sediment composition

Question 14

Where are casts typically located on a slide?

Answer 14

Near the edges of the cover slip

Question 15

Which commercial slide systems are used for urine microscopy?

Answer 15

KOVA, Urisystem, Count-10, Quick-Prep, CenSlide 2000

Question 16

Why are commercial slide systems beneficial?

Answer 16

They provide standardized sediment volume and quantification

Question 17

How should microscopic results be correlated?

Answer 17

With physical and chemical findings

Question 18

What are the three main types of microscopic urine sediment?

Answer 18

Cells, casts, crystals

Question 19

What is the function of staining in urine microscopy?

Answer 19

Enhances visibility and differentiates cellular components

Question 20

Which stain is commonly used for general urine sediment analysis?

Answer 20

Sternheimer-Malbin stain

Question 21

What color do RBCs and WBCs appear with Sternheimer-Malbin stain?

Answer 21

Purple

Question 22

What is the function of 0.5% Toluidine Blue?

Answer 22

Differentiates WBCs from renal tubular epithelial (RTE) cells

Question 23

How does 2% Acetic Acid help in urine microscopy?

Answer 23

Lyses RBCs to distinguish them from yeast, oil droplets, and crystals

Question 24

What does the lipid stain detect in urine?

Answer 24

Triglycerides (orange-red) and cholesterol (Maltese cross under polarization)

Question 25

What does the Gram stain help identify in urine?

Answer 25

Bacteria and bacterial casts

Question 26

Which stain is used to detect urinary eosinophils?

Answer 26

Hansel stain

Question 27

What finding is significant for eosinophiluria?

Answer 27

>1% eosinophils in urine

Question 28

Which stain identifies hemosiderin in urine?

Answer 28

Prussian Blue stain

Question 29

What is the clinical significance of RBCs in urine?

Answer 29

Indicates glomerular damage, trauma, or urinary tract disorders

Question 30

What is the normal range for RBCs in urine?

Answer 30

0-2 per high power field (hpf)

Question 31

What is the normal range for WBCs in urine?

Answer 31

0-5 per hpf

Question 32

What is the most significant type of epithelial cell in urine?

Answer 32

Renal Tubular Epithelial (RTE) cells

Question 33

Which condition is associated with increased RTE cells in urine?

Answer 33

Acute tubular necrosis

Question 34

What is the main protein found in urinary casts?

Answer 34

Tamm-Horsfall protein

Question 35

What does the presence of hyaline casts indicate?

Answer 35

Can be normal or indicate dehydration, fever, or stress

Question 36

What do RBC casts indicate?

Answer 36

Glomerulonephritis or severe kidney damage

Question 37

What do WBC casts suggest?

Answer 37

Pyelonephritis or kidney infection

Question 38

What condition is associated with fatty casts?

Answer 38

Nephrotic syndrome

Question 39

Which urinary casts are seen in end-stage renal disease?

Answer 39

Waxy casts

Question 40

Which urinary cast indicates severe renal failure?

Answer 40

Broad casts

Question 41

What is the significance of granular casts?

Answer 41

Indicates cellular degeneration or renal disease

Question 42

What is crystalluria?

Answer 42

Presence of crystals in urine

Question 43

What are the two types of urinary crystals?

Answer 43

Normal (physiologic) and abnormal (pathologic)

Question 44

What urine pH favors the formation of abnormal crystals?

Answer 44

Acidic urine

Question 45

What is the relevance of urinary sediment artifacts?

Answer 45

Prevents misinterpretation of contaminants as pathological findings

Question 46

What are common urinary artifacts?

Answer 46

Fibers, starch granules, air bubbles, pollen grains

Question 47

What is cylindruria?

Answer 47

Presence of urinary casts

Question 48

What does a Maltese cross appearance in urine indicate?

Answer 48

Cholesterol in lipid droplets (seen under polarized light)

Question 49

Which condition produces abundant waxy casts?

Answer 49

Chronic renal failure

Question 50

Why must microscopic urine results correlate with chemical findings?

Answer 50

Ensures accuracy and prevents reporting errors