Chapter 7 Microscopic Examination of Urine Sediment

Question 1

What is the goal of commercial urinalysis systems?

Answer 1

(1) Produce the same concentration of urine sediment volume
(2) Present the same volume of sediment for microscopic examination
(3) Control microscopic variables such as the volume of sediment view and the optical properties of the slide

Question 2

How much sediment does the UriSystem tube retain?

Answer 2

0.4 mL

Question 3

How much sediment does the Kova System retain?

Answer 3

1.0 mL

Question 4

How much sediment does the Count-10 System retain?

Answer 4

0.8 mL

Question 5

What is the ideal volume for a urinalysis? What is the acceptable range?

Answer 5

Ideal: 12 mL

Acceptable Range: 10 to 15 mL

Question 6

What is the acceptable volume for pediatric patients? What does the laboratory technician need to do when entering results?

Answer 6

Acceptable volume: 6 mL; all numeric counts from the sediment examination must be doubled.

Question 7

For sediment examination, how fast, and how long, should a sample be spun?

Answer 7

Centrifuged at 400 to 450 g for 5 minutes.

Question 8

What sediment concentration do manual techniques typically strive for?

Answer 8

12:1 concentration.

Question 9

When preparing a 12:1 concentration of urine sediment, how much urine should remain?

Answer 9

1 mL

Question 10

With more modern techniques, which action fills the slide chamber with urine sediment by the use of a transfer pipette?

Answer 10

Capillary Action

Question 11

What sediment examination method is outdated and should not be used? Why?

Answer 11

The traditional glass slide and coverslip method, because they do not yield standardized, reproducible results.

Question 12

What are the two ways microscopic examination results can be reported?

Answer 12

(1) Qualitatively assessed per field of view (rare, few, moderate, etc)
(2) Enumerated as a range of formed elements present (0 to 2, 2 to 5, etc)

Question 13

When a microscopic examination is performed, the volume of sediment viewed in each microscopic FOV is determined by what two factors?

Answer 13

(1) The optical lenses of the microscope

(2) The standardized slide system used

Question 14

How could interlaboratory result comparisons be possible and comparisons between manual and automated microscopy systems be facilitated?

Answer 14

By relating sediment elements as the “number present per volume of urine” instead of per low- or high-power field.

Question 15

What should the settings be when centrifuging a urine specimen?

Answer 15

400 to 450 g for 5 minutes

Question 16

Sternheimer-Malbin Stain uses?

Answer 16

A supravital stain that characteristically stains cellular structures and other formed elements.

Enables detailed viewing and differentiation of cells, cast inclusions, and low retractile elements (e.g., white blood cells, hyaline casts, mucus)

Question 17

What is a disadvantage of using Sternheimer-Malbin stain?

Answer 17

In strongly alkaline urines, this stain can precipitate, which obstructs the visualization of sediment components.

Question 18

0.5% solution of toluidine blue uses?

Answer 18

A supravital stain; a metachromatic dye that stains various cell components differently and enhances the nuclear detail of cells.

Aids in differentiating WBCs and renal tubular epithelial cells.

Question 19

Acetic acid stain uses?

Answer 19

It can be helpful in identifying white blood cells, especially in hypertonic urine.

Question 20

Disadvantage of using acetic acid?

Answer 20

Carcinogenic; red blood cells become lysed.

Question 21

What are the two common Fat or Lipid stains?

Answer 21

Sudan III or oil red O

Question 22

Fat stains uses?

Answer 22

Stains triglycerides (neutral fat) droplets a characteristic orange (Sudan III) or red (oil red O) color.

Used to confirm the presence of fat in urine.

Question 23

Gram Stain uses?

Answer 23

Identifies and classifies bacteria as gram-negative or gram-positive.

Aids in the identification of bacterial and fungal casts.

Question 24

Prussian Blue Reaction uses?

Answer 24

Identifies hemosiderin, which can be free-floating, in epithelial cells, or in casts.

Question 25

Hansel stain uses?

Answer 25

Aids in the identification of eosinophils

Question 26

Uses of phase-contrast microscopy?

Answer 26

Enhances the imaging of translucent or low-refractile formed elements; can be used for evaluation of RBC morphology.