---
type: "WebPage"
title: "Particle count testing according to ph. eur. 2.9.19 (Method 1)"
description: "Would you like to carry out particle count testing according to Ph. Eur. 2.9.19, Method 1? Ensure the purity of your injectable preparations and infusions In the pharmaceutical sector, patient safety is a priority. Contamination by particles invisible to the..."
resource: "https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-injectable-drugs/particle-count-testing-according-to-ph-eur-2-9-19-method-1/"
tags: ["EN", "Anaïs DECAUX"]
timestamp: "2026-06-18T13:28:49Z"
published: "2026-06-18T13:28:48Z"
language: "en"
author: "Laure Durieux"
---

# Particle count testing according to ph. eur. 2.9.19 (Method 1)

## Would you like to carry out particle count testing according to Ph. Eur. 2.9.19, Method 1?

### Ensure the purity of your injectable preparations and infusions

In the [pharmaceutical](https://filab.fr/en/sectors-of-activity/analysis-industry-pharmaceuticals.md) sector, patient safety is a priority. Contamination by [particles](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-injectable-drugs.md) invisible to the naked eye in injectable preparations represents a critical health risk (embolisms, immune reactions).

Ensure the compliance and safety of your injectable preparations with FILAB, an expert laboratory in particle count testing according to [European Pharmacopoeia 2.9.19](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-injectable-drugs/particle-counting-laboratory-according-to-ep-2-9-19.md)Method 1 by Light Obscuration (LO). Our accredited laboratory carries out precise analysis to detect and quantify visible and sub-visible particles, ensuring the quality and integrity of your pharmaceutical products.

### What is Method 1 of ph. eur. 2.9.19?

Method 1 is based on **particle counting by light obscuration (Light Obscuration)**. It is the reference (preferred) method of the European Pharmacopoeia for injectable solutions and infusion preparations.

### The technical principle

When a suspended particle passes through a laser beam, it blocks part of the light. The sensor measures this drop in intensity to instantly determine the number and size of the particles.

### Regulatory thresholds (ph. eur. 2.9.19)

The requirements vary depending on the container’s nominal volume:

| **Container volume** | **Particle size** | **Maximum limit per container / mL** |
| --- | --- | --- |
| **Large Volumes (> 100 mL)** | >=  10 µm   >= 25 µm | 25 per mL   3 per mL |
| **Small Volumes (<= 100 mL)** | >= 10 µm   >=25µm | 6000 per container   600 per container |

##  

## The FILAB laboratory carries out particle count analysis by LO (Light Obscuration) for injectable solutions: vaccines

### Our key services

- **Routine analysis and batch release** for your finished products.
- **Stability testing** to monitor particle evolution over time.
- **Method development and validation** specific to your matrices (adaptations may be required if the product is viscous or prone to microbubbles).
- **Support in the event of an Out-of-Specification (OOS):** if thresholds are exceeded, we help you investigate (with the option to switch to Method 2 by optical microscopy to identify the nature of the particles).

### Why choose the FILAB laboratory for particle count testing according to Ph. Eur. 2.9.19 Method 1?

FILAB offers industrial companies specializing in the medical and pharmaceutical sectors technical expertise and a [state-of-the-art analytical platform](https://filab.fr/en/our-technical-resources.md) to respond as effectively and quickly as possible (with the option of carrying out these analysis urgently) to their requests and provide the most suitable services and tailored support.

To address these issues with precision and reliability, FILAB offers tailored support for [particle count testing](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-deposit-contamination/laboratory-identification-counting-particulate-contmaninant.md) according to Method 1 of Ph. Eur. 2.9.19, as well as according to other standards…

### FILAB is COFRAC ISO 17025 accredited

FILAB, accredited **COFRAC ISO 17025**, guarantees reliable analysis that comply with the requirements of the **European Pharmacopoeia** for particulate counting of injectable products. This accreditation attests to our expertise and our commitment to delivering precise results to ensure the safety and compliance of your pharmaceutical formulations.

 For pharmaceutical products
- Foreign body and/or contaminant identification by SEM-EDX and binocular micro-infrared spectroscopy, according to Ph. Eur. 2.9.52 standards
- Particle count testing by optical microscopy and image analysis, according to USP 788/789 and Ph. Eur. 2.9.19 (Method 2)

 For medical devices
- Particle counting by [optical microscope](https://filab.fr/en/our-technical-resources/laboratory-of-analysis-and-observation-by-optical-microscope-mo.md) according to current standards: ISO 19227, ISO 10993-19, USP 788, Ph. Eur. 2.9.19, AAMI TIR 42
- Particle identification by [SEM-EDX](https://filab.fr/nos-moyens-techniques/laboratoire-d-analysis-par-microscopie-electronique-a-balayage-meb-edx/) and [µ-IRTF](https://filab.fr/en/our-technical-resources/laboratory-analysis-ftir-microscopy.md) according to current standards: ISO 10993-19, Ph. Eur. 2.9.52, Ph. Eur. 2.2.24, AAMI TIR 42

### Find the standards FILAB masters for performing particulate counting:

[ISO 19227 refers to AAMII TIR 42 (medical)](https://filab.fr/en/sectors-of-activity/laboratory-analysis-medical-devices/particle-counting-laboratory-according-to-the-aami-tir42-standard.md)

[ISO 16232 (automotive)](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-deposit-contamination/automotive-contaminant-analysis-according-to-iso-16232.md)

[Particle count testing according to USP 788 (pharmaceutical)](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-particulate-contaminant/particle-counting-laboratory-according-to-usp-788.md)

## Our FAQ

 How can i get a quote from FILAB?
To obtain a quote, you can contact our teams via our contact form, by phone, or by email.
Simply send us your requirements (material type, analysis requested, any applicable standard, urgency, number of samples, etc.). We will then send you a personalized technical and pricing proposal within 24-48 hours.

 What is the typical analysis turnaround time?
Lead times vary depending on the nature of the analysis and the complexity of the expert assessment project.
However, FILAB is committed to providing fast turnaround times tailored to your constraints and industrial urgencies.

 Why carry out particle count testing on injectable products?
The presence of undissolved particles can pose a risk to patient safety and compromise the quality of injectable medicines. Particle control makes it possible to verify product compliance with regulatory requirements and ensure their integrity.

 What is particle count testing according to Ph. Eur. 2.9.19 (Method 1)?
Method 1 of European Pharmacopoeia 2.9.19 makes it possible to detect and quantify non-visible particles present in injectable preparations and infusion solutions. It is based on the principle of light obscuration and is the preferred reference method for the control of subvisible particles.

 What is the principle of Method 1 by light obscuration?
The sample is drawn through a cell crossed by a light beam. When a particle passes in front of the detector, it causes a decrease in light intensity. This variation makes it possible to determine the size and number of particles present in the solution.

 In which cases is Method 1 not suitable?
Certain formulations can interfere with light obscuration measurement:

- opaque or colored solutions;
- highly viscous products;
- samples containing air bubbles;
- suspensions or emulsions.

In these situations, the European Pharmacopoeia recommends using Method 2 by microscopy.

 What is the difference between Method 1 and Method 2 of PE 2.9.19?
| Method 1 | Method 2 |
| --- | --- |
| Light obscuration | Microscopy |
| Preferred method | Alternative method |
| Fast and automated | Longer and manual |
| Suitable for clear solutions | Suitable for viscous or less transparent products |
| Automatic particle counting | Microscopic observation and counting |

In some cases, both methods may be used successively to confirm a product's compliance.

 Why use a specialized laboratory for particle counting?
The FILAB laboratory has:

- qualified and calibrated instruments;
- expertise in interpreting results;
- a controlled environment that limits contamination;
- the ability to investigate the origin of particles in the event of non-compliance.

Particle counting can also be supplemented by contaminant identification analysis (SEM-EDX, µ-IR, Raman, etc.) in order to trace the source of contamination and secure the manufacturing process.