# Commission Directive 2006/56/EC of 12 June 2006 amending the Annexes to Council Directive 93/85/EEC on the control of potato ring rot, Appendix 4: Determination of contamination level in IF and FISH tests

Extent: E+W+S+N.I.

1.. Count the mean number of typical fluorescent cells per field of view (c)
2.. Calculate the number of typical fluorescent cells per microscope slide window (C)
C = c × S/s
where
S
=
surface area of window of multispot slide, and
s
=
surface area of objective field.
s = πi2/4G2K2
where
i
=
field coefficient (varies from 8 to 24 depending upon ocular type)
K
=
tube coefficient (1 or 1,25)
G
=
magnification of objective (100x, 40x etc.).
3.. Calculate the number of typical fluorescent cells per ml of resuspended pellet (N)
N = C × 1 000/y × F
where
y
=
volume of resuspended pellet on each window, and
F
=
dilution factor of resuspended pellet.

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Source: https://www.legislation.gov.uk/eudr/2006/56/annex/I/appendix/4 (the official version)
Page: https://openlegislation.uk/eu-directive-2006-56/annex-I/appendix-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.