ERP Micro December 2019

N x = number of samples tested at level x ( L 1 or L 2 ) with the reference method by all the collaborators.

1

( ) alt x x CP p N + =

2

where

3

CP x = number of samples with a confirmed positive result obtained with the alternative method at level x

4

( L 1 or L 2 ) for all the collaborators;

5

N x = number of samples tested at level x ( L 1 or L 2 ) with the alternative method by all the collaborators.

6

7

) ND-PD 3 max

2

( ) ( ) ref alt ref alt p p p = × + + + − + × + ( ) ( ) ( ( x N p

)

)

(

8

where

9

N x = number of samples tested for level x ( L 1 or L 2 ) with the reference method by all the collaborators.

0

1

Negative Deviation – Negative results of the alternative method when the corresponding reference method

2

result is positive.

3

Positive Deviation – positive result of the alternative method when the corresponding reference method

4

result is negative

5

Note * Positive and negative deviations are not the same as false positive and false negative results for an

6

unpaired study.

7

The AL is not met when the observed value is higher than the AL. When the AL is not met,

8

investigations should be made (e.g. root cause analysis) in order to provide an explanation of the observed

9

results. Based on the AL and the additional information, it is decided whether the alternative method is

0

regarded as not fit for purpose. The reasons for acceptance of the alternative method when the AL is not

1

met shall be stated in the study report. In this study, fractional recovery was observed at Level 1. The

2

calculations are the following (See Table 9), according to the EN ISO 16140-2 (2016):

3

43