EN ISO 17601:2018

European foreword
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Test materials
6 Apparatus
7 Procedure
8 Examination of the critical steps of the [q]PCR assay
9 Expression of the results of the [q]PCR assay
10 International ring test
11 Test report
Annex A (informative) - Description of principal steps of
        TaqMan[R] [q]PCR assay
Annex B (informative) - International ring-test for evaluating
        [q]PCR to quantify the abundance of selected microbial
        gene sequences from DNA directly extracted from soil
Bibliography

ISO 17601:2016 specifies the crucial steps of a quantitative real-time polymerase chain reaction (qPCR) method to measure the abundance of selected microbial gene sequences from soil DNA extract which provides an estimation of selected microbial groups.It is noteworthy that the number of genes is not necessarily directly linked to the number of organisms that are measured. For example, the number of ribosomal operon is ranging from one copy to 20 copies in different bacterial phyla. Therefore, the number of 16S rRNA sequences quantified from soil DNA extracts does not give an exact estimate of the number of soil bacteria. Furthermore, the number of sequences is not necessarily linked to living microorganisms and can comprise sequences amplified from dead microorganisms.