ChemoMetec NucleoCounter, User Manual

Page: 47 / 76

6 Total and viability count
30
%viability: The percentage of viable cells in the original cell
suspension.
C
t
: The total concentration of cells in the
NucleoCassette (the displayed result of the total
cell count).
C
nv
: The concentration of non-viable cells in the
NucleoCassette (the result displayed when counting
the non-viable cells).
M
t
: The multiplication factor used for the total cell
count.
M
nv
: The multiplication factor used for the counting of
non-viable cells (most often 1).
Example of calculation of %viability:
The stabilized lyzate is prepared using 200 µl of the cell
suspension, 200 µl Lysis buffer and 200 µl Stabilizing buffer.
Thus, the multiplication factor (M
t
) is 3. The result of the
total cell count (C
t
) is 6,7∙10
5
cells/ml.
Counting the non-viable cells is done without dilution of the
cell suspension prior to the analysis and the multiplication
factor (M
nv
) is 1. The result of the count of non-viable cells
(C
nv
) is 3,0∙10
4
cells/ml.
The calculation of %viability is shown below.
98,5% 100%
3 10 6,7
1 10 3,0 - 3 10 6,7
100%
M C
M C M C
%viability
5
4 5
t t
nv nv t t
 
 
   
 

  

6.4 Dilute the samples
As mentioned earlier the NucleoCounter is able to count cells
in the range 5x10
3
- 2x10
6
cells/ml, the optimal range being
1x10
5
– 2x10
6
cells/ml. Therefore it can be necessary to dilute
or concentrate the cell samples. There are two recommended
methods to dilute a cell sample; either it can be diluted using
the Lysis buffer and the Stabilizing buffer or it can be
diluted prior to addition of Lysis buffer and Stabilizing
buffer.
When using the Lysis buffer and Stabilizing buffer to dilute
the cell sample, the procedure described above is followed,
only the amounts of Lysis buffer and Stabilizing buffer added
to the samples are altered. Note that it is important to add
equal volumes of Lysis buffer and Stabilizing buffer to the
samples. For examples of dilution using the Lysis buffer and
Stabilizing buffer, see the table below.