Direct Microscopic Somatic Cell Count Guidelines

1
Direct Microscopic Somatic Cell Count Guidelines

• Prepared By
• Laboratory Development Section
• Division of Microbiology
• Bureau of Foods
• Food and Drug Administration
• November 1972

Adapted to Slides By DHHS,PHS,FDA,CFSAN,OC,DCP La
boratory Quality Assurance Branch January 2003
2
Rules for identifying and counting somatic cells

• Leukocytes have a nucleus
• Nuclear mass composition
• Recognizable form
• One or more lobes
• Lobes or units are bridged by nuclear material
• Some cells are granular in appearance
• Some distortion is expected because of treatment
• Nuclear mass stains dark blue or blue-green
• Count nuclear mass that bears resemblance to a
  typical nucleus

3
Rules contd

• Cytoplasm normally surrounds the nucleus.
• Stains light blue,
• Not stained and appears as a clear zone, or
• Disintegrated and not present.
• Do not count cells without a stained nuclear mass
  (ghost cell)
• Cell size.
• Nuclear mass of a countable cell is 8 microns.
• Fragments of a countable cell with at least 50
  of the nuclear mass visible and 4 microns.

4
Rules contd

• Clump of cells
• Nuclear mass must be clearly delineated to count
  individual cell(s).
• If no clear delineation, count clump as one cell.
• Field boundaries
• Do not over extend the field or strip boundaries
• Count cells touching top or bottom edge of strip,
  not both.

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Form FDA 2400d (6/05)DMSCC 25.g. Identifying and
counting somatic cells.

• Cells possess a nucleus stained dark blue
  (bovine) or blue-green (caprine).
• Cells generally 8 microns or larger (bovine,
  caprine may be smaller) do not count cells less
  than 4 microns fragments counted only if more
  than 50 of nuclear material is visible.
• Cluster of cells counted as one unless nuclear
  unit(s) are clearly separated focus up and down
  to ensure that there are no bridges connecting
  nuclear masses.
• Count cells touching only the top or bottom half
  of the strip.
• IF IN DOUBT, DO NOT COUNT.

6
A, B and C are countable cells.
D is not a countable cell since it is less than 8
microns in diameter.
Circled items are bacteria or artifacts that bear
no resemblance to a typical nucleus and not
counted. (3 cells)
1
7
A and B are countable cells. (2 cells)
2
8
A is a countable cell. (1 cell)
3
9
A and B are countable cells. Both are surrounded
by disintegrating cytoplasm, however the nuclear
material remains intact and each resembles a
typical nucleus. (2 cells)
4
10
A D are typical cells (multi-lobed nuclei).
E is cellular debris and not counted. (4 cells)
5
11
One cell with nuclear lobes connected by a
nuclear bridge. (1 cell)
6
12
B and D are typical cells. (2 cells)
A and C are cytoplasmic debris and not counted.
7
13
B is a countable cell.
A is a ghost cell (no nuclear material) and not
counted. (1 cell)
8
14
One cell with a disintegrating nucleus, however
greater than 50 of the multi-lobed nuclear mass
is visible. (1 cell)
9
15
Nuclear Bridge
A-E are typical cells. (5 cells)
10
16
A is a typical cell with a multi-lobed nucleus.
B is a typical monocyte. Both are counted. (2
cells)
11
17
A is a single cell with cytoplasm. (1 cell)
12
18
Nuclear bridges
All are cells.
B and E are bi-lobed with nuclear bridges. (6
cells)
13
19
A is less than 8 microns in diameter and not
counted.
B has a disintegrating nucleus with greater than
50 of the nuclear mass visible and is counted.
14
C is a typical multi-lobed cell. (2 cells)
20
A, C, and D are typical cells. Cell D is
touching the top edge of the field and not
counted.
B is cytoplasmic debris (less than 50 of nucleus
present) and not counted. (2 cells)
15
21
Nuclear bridge?
A-G are typical cells. Cell B is not counted as
it touches the top edge of the field. (7 cells)
16
22
A, B, C, and E are typical cells.
D is a cell with a large amount of disintegrating
cytoplasm.
F is debris, not a cell. (5 cells)
17
23
A-C are typical cells.
Blue-circled item is a bacteria or artifact that
bears no resemblance to a typical nucleus and not
counted as a cell. (3 cells)
18
24
Cell A appears to be gt8 microns.
Cell C is not counted as it touches the top edge.
B, D, E, and F are typical, countable cells. (5
cells)
19
25
A and B are debris. (0 cells)
20
26
A is a typical cell.
B and C are cytoplasmic debris. (1 cell)
21
27
A and D are typical cells.
Cell B is a fragment greater than 50 of original
size.
Cell C has disintegrating nuclear material
greater than 50 of original composition. (4
cells)
22
28
A and B are typical cells.
C and D are cells showing early degeneration. (4
cells)
23
29
A is a typical cell. (1 cell)
24
30
A E is a clump of typical cells. (5 cells)
25
31
A, B, and I are bi-lobed cells.
C is tri-lobed.
D contains 4 nuclear masses.
E, F, G, and H are mononuclear cells.
J is a disintegrating cell. (10 cells)
26
32
Nuclear Bridges?
A, B, C, and D are typical cells. (4 cells)
27
33
A is a typical cell showing cytoplasmic
degeneration.
B is cellular debris. (1 cell)
28
34
A and B are typical cells, but A is touching the
top edge and not counted.
C is a ghost cell. (1 cells)
29
35
A is a disintegrating cell.
B is typical. (2 cells)
30
36
Final Count

• The total count for 30 slides of one strip count
  88 cells