Urine Sediment Identification
Penny S. Stevens, MBS, MT(ASCP), CLS(NCA)
Sr. International QA/QC Medical Technologist
SMILE, Johns Hopkins University
Course Objectives
Review the kidney structure
 Review rapid chemical tests
 Identify normal and abnormal urine sediment
 Review steps for accurate sediment ID
 Case studies

2
Kidney Structure - Overview


Approximately 1 million
nephrons in each
kidney
Waste products and
water pass along the
tubule


Water, salts, sugar, &
other large molecules
reabsorbed within limits.
Excess products &
Urine are excreted.
3
Rapid Chemical Test
Bilirubin
 Blood
 Glucose
 Ketones
 pH

Protein
 Urobilinogen
 Nitrite
 Leukocytes
 Specific Gravity

4
Normal & Abnormal
Microscopy Review

Cells

Casts
Uric Acid Crystals

Crystals
RBC’s & WBC’s
Epithelial Cast
5
Microscopy - Cells

Red Blood Cell

What rapid chemistry
result do you expect to
be positive?

Blood
Leukocyte Esterase
Possibly Nitrite


6
Microscopy - Cells

White Blood Cell

What rapid chemistry
result do you expect to
be positive?

Leukocyte Esterase
7
Microscopy - Cells

Squamous Epithelial

What rapid chemistry
result do you expect to
be positive?

Possibly Nitrite
8
Microscopy - Cells

Renal Epithelial

What rapid chemistry
result do you expect to
be positive?

Possibly Protein
9
Kidney Structure – Cast
Formation

Protein – Tamm-Horsfall



T-H Protein, albumin &
immunoglobulin



Secreted by tubule cells
Distal convoluted tubule
(DCT).
Combine to form cast
Include tubule contents
Illustration:


Protein secretion (green
dots)
Hyaline cast (formed in the
collecting duct.
10
Cast Formation

DST protein secretion

Tubule contents
wrapped into protein
matrix



None = Hyaline
Cells = Cellular Cast
Progression




Cellular
Coarse Granular
Fine Granular
Waxy – (Theory)
11
Microscopy – Cast ID

Hyaline Cast

Key Features







Transparent
Cylindrical
Rounded Ends
Colorless
Homogenous
Nearly Parallel sides
No Dark Edges
12
Microscopy – Cast ID

Hyaline Cast

What rapid chemistry
result do you expect to
be positive?

Protein:

Negative – 1+
13
Microscopy – Cast ID

Cellular Cast – (Renal)

Key Features






Cellular: Few – Numerous
Cylindrical
Rounded Ends
Color – depends on the
contents
Nearly Parallel sides
No Dark Edges
14
Microscopy – Cast ID

Fatty Cast – Polarized
Light


Starch - Polarized
Maltese cross
Similar to starch

What rapid chemistry result
do you expect to be
positive?

Protein
Other rapid chemistriesDepends on the contents15
Fat - Polarized

Microscopy – Cast ID

Granular Cast


Coarse Granular Cast

Key Features





Fine Granular Cast
Coarse - black
Fine – grey/pale yellow
Cellularity Indeterminate
Cylindrical
Rounded Ends
Nearly Parallel sides
No Dark Edges
16
Microscopy – Cast ID

Granular Cast
(Hemoglobin)

What rapid chemistry
result do you expect to
be positive?

Protein
Other - Depends on
the origin:


Blood/Hemoglobin
17
Microscopy – Cast ID

Waxy Cast

Key Features






Opaque (Refractive)
Homogeneous (non-cellular)
At Least One Flat/Blunt End
Short
Possibly Cracked, Serrated or
Convoluted
Nearly Parallel Sides
18
Microscopy – Cast ID

Waxy Cast

What rapid chemistry
result do you expect to
be positive?

Protein

>3+
19
Microscopy – Artifact

Fibers

Key Features




Refractile
Flat
Parallel Sides
Dark Edges
20
Cast Comparison
Hyaline Cast



Transparent
Cylindrical
Rounded Ends
Waxy Cast



Opaque
Cylindrical
Blunt Ends
Fiber



Refractile
Flat
Dark Edges21
Urine Sediment Training

Questions??
22