ChemoMetec NC-100 - Manual (Page 41)

6 Total and viability count
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After approximately 30 seconds the NucleoCounter shows the result in the display and
on the computer if one is connected.
Examine the result of the analysis. The measurement range of the NucleoCounter is
5•10
3 - 2•10 6 cells/ml. If the cell concentration of the stabilized lyzate is outside the
measurement range then the cell suspension has to be concentrated (e.g. by
centrifugation) or diluted (see section 6.4 below). The measurement is then repeated.
The optimal measurement range for cell counting with the NucleoCounter is 10
5 –2•10 6
cells/ml.
Please notice that the displayed result is based on the stabilized
lyzate loaded into the NucleoCassette.
In other words, the result has to be multiplied with the
multiplication factor (in this case 3) to calculate the concentration
of cells in the cell suspension.
6.2 Counting non-viable cells
No pre-treatment of the cell suspension is needed to count the non-viable cells. The cell
suspension is mixed to obtain a homogenous suspension and the cells are loaded
directly into the NucleoCassette. In this way only the DNA of non-viable cells will be
stained.
Perform the measurement (for details see sections 5.2 and 5.3).
The result is displayed on the NucleoCounter and the computer if one is connected after
approximately 30 seconds.
Examine the result to make sure that the concentration of cells is in the measurement
range 5•10
3 – 2•10 6 cells/ml. Often the result of a non-viable cell count is below the
optimal measurement range. This is generally due to the low fraction of non-viable cells
compared to the total cell concentration. The result of the NucleoCounter should be
regarded as reliable in these cases but the operator must
be aware that a high relative
error is associated with these results due to the nature of count statistics.
Generally the cell suspension is not diluted prior to counting the non-viable cells. If the
cell suspension is diluted prior to the analysis, remember to multiply with the
multiplication factor to obtain the actual concentration of non-viable cells in the cell
suspension.