ISO TS 12869-2019 PDF

Full title and description

Water quality — Detection and quantification of Legionella spp. and/or Legionella pneumophila by concentration and gene amplification by quantitative polymerase chain reaction (qPCR). This Technical Specification defines a qPCR-based method for detecting and quantifying Legionella species (including L. pneumophila) in water samples, with requirements for method performance, quality control and reporting.

Abstract

This document specifies a standardized workflow using concentration, DNA extraction and quantitative PCR (qPCR) to detect and quantify Legionella spp. and L. pneumophila in environmental water samples. It sets out methodological requirements, validation and performance criteria, quality-control measures and how results should be expressed (genome units per litre). The specification notes limitations (possible matrix interference and that qPCR does not indicate physiological/viability state).

General information

• Status: Published (Technical Specification).
• Publication date: April 2019.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 07.100.20 — Microbiology of water.
• Edition / version: Edition 2 (2019).
• Number of pages: 47.

Basic bibliographic and lifecycle details as published by ISO.

Scope

Applies to the detection and quantification of Legionella spp. and L. pneumophila in all types of water (potable, cooling tower, hot/cold water systems, etc.) using concentration and qPCR. The scope includes general methodological requirements, sample handling, performance evaluation, validation and quality-control procedures. The document notes that some sample matrices or treatment chemicals may affect sensitivity and that qPCR-based results report genome units per litre and do not indicate bacterial viability.

Key topics and requirements

• Sample concentration and pre-treatment procedures to recover Legionella cells from water.
• DNA extraction approaches suitable for environmental water matrices.
• qPCR assay design, target selection and amplification conditions for Legionella spp. and L. pneumophila.
• Performance criteria and validation requirements (sensitivity, specificity, limits of detection/quantification, robustness) including clauses on method characterization and validation.
• Quality-control measures: controls, standards, inhibition checks and acceptance criteria for results.
• Expression and reporting of results as genome units (GU) per litre, and guidance on interpreting qPCR data given limitations on viability information.

Typical use and users

Intended users include environmental and public-health laboratories, water-supply and facility monitoring teams, diagnostic kit developers and validation laboratories, regulators and consultants involved in Legionella surveillance and outbreak investigations. The method has been used as a basis for validation studies and alternative rapid assays (e.g., LAMP) and is referenced in peer-reviewed validations and method-comparison studies.

Related standards

Closely related ISO documents include ISO 11731 (Water quality — Enumeration of Legionella, culture-based methods) and earlier/superseded editions of this Technical Specification (ISO/TS 12869:2012). ISO/TS 12869:2019 is intended to complement culture methods by providing molecular detection/quantification guidance.

Keywords

Legionella; Legionella pneumophila; water quality; qPCR; quantitative PCR; detection; quantification; genome units per litre; method validation; sampling; DNA extraction; environmental microbiology.

FAQ

Q: What is this standard?

A: ISO/TS 12869:2019 is a Technical Specification that standardizes a qPCR-based method for detecting and quantifying Legionella species (including L. pneumophila) in water samples, with requirements for performance, validation and quality control.

Q: What does it cover?

A: It covers sample concentration, DNA extraction, qPCR assay conditions, performance and validation criteria, quality-control procedures and how to express and report results (genome units per litre). It also describes limitations such as matrix interference and the inability of qPCR to distinguish viable from non‑viable cells.

Q: Who typically uses it?

A: Environmental and public-health laboratories, water utilities, facility managers, regulatory authorities, test-kit manufacturers and researchers involved in Legionella monitoring, surveillance and method development/validation. The specification has been used as the basis for laboratory validations and new assay validations in the literature.

Q: Is it current or superseded?

A: ISO/TS 12869:2019 is the current edition (published April 2019) and supersedes ISO/TS 12869:2012. Users should check national/regulatory requirements for adoption dates or amendments.

Q: Is it part of a series?

A: It is developed under ISO/TC 147/SC 4 (microbiological methods for water) and is complementary to other Legionella-related standards such as ISO 11731 (culture-based enumeration) and related technical guidance for environmental microbiology.

Q: What are the key keywords?

A: Legionella; L. pneumophila; qPCR; detection; quantification; water quality; genome units; validation; sampling; DNA extraction.