The Native Antigen Company is part of LGC Clinical Diagnostics - Learn More

0 Items
Select Page

Endotoxin Testing Services

The Native Antigen Company offers services to quantitate endotoxin in samples using the LAL assay.

About Endotoxin Testing

What are endotoxins?

Endotoxins are small (~10 kDa) lipopolysacchride (LPS) molecules associated with the outer membranes of gram-negative bacteria. They are released from bacteria at low levels during normal cell growth but also in much larger quantities after cell death, when their cell membranes rupture and disintegrate. The released LPS is composed of three distinct regions: O antigen, a core domain and Lipid A. O antigen is found on the outermost domain of the LPS molecule and is associated with immunogenicity; Core domain is composed of sugars and other non-carbohydrates and attaches directly to Lipid A; Lipid A anchors the LPS into the bacterial membrane and it is this part of the molecule which is responsible for the toxicity of gram-negative bacteria. Indeed, endotoxin is known to be a potent inflammatory mediator and pyrogen in vivo and can result in toxic shock, tissue injury, and death.

Why are endotoxins a problem in bioproduction?

Recombinant proteins, particularly those manufactured in E. coli, are often contaminated with endotoxin. In fact, a single E. coli cell can release up to 2 million LPS molecules. These contaminants are hydrophobic giving them a strong affinity for laboratory plasticware and are stable at high temperature, making it impossible to destroy them by sterilization. Water used to make routine buffers and solutions can be a source of endotoxins as can be reagents such as sera and media. Poor aseptic technique is another potential source of LPS. During the bioproduction process, the host cells will normally be removed by centrifugation or filtration; however, any endotoxin contamination will remain and a significant proportion is likely to be carried through the purification process. As such, endotoxins are frequent contaminants of recombinant DNA and protein solutions. Unfortunately, the presence of these toxins, even at relatively low levels, can significantly affect the results of both in vivo and in vitro biological assays causing non-specific cellular responses and false readings in cell-based assays. Endotoxin-free production may be carried out to try and reduce the LPS burden but ultimately this is no guarantee of success, and endotoxin levels above acceptable thresholds may still be present within the final preparation.

Endotoxin is measured in endotoxin units per milliliter (EU/mL) where 1 EU equals approximately 0.1-0.2 ng endotoxin/ml of solution. Generally, endotoxin levels below 0.1 EU/ml are considered acceptable for in vivo studies. However, even lower amounts of endotoxin have been shown to cause changes in physiology in vivo and it is likely that acceptable levels will vary across different assays and experimental conditions.

About Endotoxin Testing

Testing for endotoxins

We offer a service to detect and quantitate the amount of endotoxin in your sample using a kinetic chromogenic assay, called the Limulus Amebocyte Lysate (LAL) test. LAL comprises blood cells (amebocytes) from the Atlantic horseshoe crab (Limulus polyphemus) which clot when they encounter bacterial endotoxin lipopolysaccharides. This clotting can be detected using a chromogenic substrate where the enzymatic reaction between the endotoxin and lysate produces a yellow colour. The intensity of this colouration is directly linked to the quantity of endotoxin present in the sample.

What we offer

+ We use a chromogenic method that has been FDA approved for all stages of therapeutic product development.

+ Multiple samples types can be tested, including DNA, recombinant proteins and antibodies, with the sensitivity to detect endotoxin levels down to 0.005 EU/ml.

+ Routine test results are completed in 1-2 days.


Test samples are compared to a standard curve prepared from known endotoxin concentrations and all tests are performed in duplicate alongside a positive and negative control, as recommended by the harmonized USP Bacterial Endotoxins Test (BET) and the FDA guideline for LAL testing.

Sensitivity (EU/ml)
Range (EU/ml)
Price / Sample
1-3 samples
4-6 samples
7-12 samples
10 - 0.1
£378   LAL84101-03
£321   LAL84101-12
5 - 0.05
£344   LAL84102-06
£325   LAL84102-12
1 - 0.01
£368   LAL84103-03
£332   LAL84103-06
£314   LAL84103-12
0.5 - 0.005
£390   LAL84104-03
£352   LAL84104-06
£333   LAL84104-12


Get in Touch with a Member of our Team

We sometimes send exclusive information and offers to our customers - please let us know if you are happy to receive these

13 + 9 =

The Native Antigen Company expands its range of Omicron antigens to include BA.5 variant

New antigens support research into BA.5 variant, currently responsible for over half of global COVID-19 cases Oxford, UK, 02 November 2022: The Native Antigen Company (part of LGC Clinical Diagnostics), one of the world’s leading suppliers of reagents that enables...

The Role of Serology in Tracking COVID-19 Mutations

This article was originally published on Clinical Lab Products. As SARS-CoV-2 began its global proliferation in early 2020, scientists hastened to investigate its biology, develop diagnostic tests, and design candidate vaccines, marking one of the most...

Preparing for Disease Y: A Better Serological Toolbox

This article was originally published on Clinical Lab Manager. It’s been over a year since the World Health Organization (WHO) declared COVID-19 a pandemic. SARS-CoV-2 has since infected 200 million people, resulting in nearly 4 million deaths and substantial economic...

Keeping Up with the New SARS-CoV-2 Variant Nomenclature

If you’ve been struggling to make sense of SARS-CoV-2 variant nomenclature, you’re not alone. Due to the existence of multiple genomic sequence databases, various naming systems are in use for the rapidly growing range of SARS-CoV-2 variants of concern/interest. In a...

Making Sense of the SARS-CoV-2 Spike Mutations

Through much of 2020, SARS-CoV-2 accumulated mutations at a steady, yet unspectacular rate. However, as global cases approached 100 million by the end of the year, multiple variants began to emerge. Exhibiting more considerable genomic changes, some variants have...

D614G: Putting the Mutation in Perspective

Since the emergence of SARS-CoV-2, scientists have speculated about the risks of mutation and what this could mean for therapeutics and vaccines. In this blog, we explore the nature viral mutation, what is known about the D614G mutant of SARS-CoV-2, and introduce our...

The Endemic Coronaviruses and What They Might Tell us About COVID-19

While less-well known than some of their counterparts, the 229E, NL63, OC43, and HKU1 human coronaviruses are a significant cause of respiratory disease worldwide. The evolutionary histories and host associations of the endemic coronaviruses also provide important...

Q&A: An Insight Into COVID-19 Serology

During the course of the current coronavirus pandemic, we have all been aware of the urgent need for nucleic acid testing to identify people currently infected with SARS-CoV-2. The second form of testing needed are serological immunoassays, which can identify past...

A Q&A with David Flavell of Leukaemia Busters

In this blog, we speak with Dr. David Flavell about his scientific career, the legacy of Leukaemia Busters, and the recent impact that COVID-19 has had on his research.Tell me about your scientific background David. I was born in a seaside town called Southport in the...

Avoiding the Immunopathology Pitfalls of a COVID-19 Vaccine

In the second of a three-part series on COVID-19 vaccines, we explore the potential challenges in stimulating safe vaccine responses and outline the role that diagnostics will play in guiding their development.Rogue Responses Antibodies play a crucial role in...

Designing for Differentiation: Why We Need Highly Specific Diagnostics for a COVID-19 Vaccine

Assessment of vaccine-induced immune responses in clinical trials will require highly specific diagnostic assays to ensure safety. This blog was originally published on Clinical Lab Manager.The Vaccine Race Vaccines are the most effective means of preventing...

An Early Look at Vaccines for COVID-19

In the first of a three-part series on the design, immunology and manufacture of COVID-19 vaccines, we take an early look at the major technologies under development and weigh-up the challenges these vaccines will face in reaching late-phase clinical trials.Why We...

Why We Need Antigen and Antibody Tests for COVID-19

RT-PCR is the workhorse of viral diagnosis and has been invaluable in COVID-19 case confirmation and isolation guidance. However, while fast and sensitive, PCR suffers from some inherent drawbacks that limit it to diagnosis during the acute phase of infection. To...

Novel Coronavirus Antigens Now Available

The Native Antigen Company is now offering recombinant S1 and S2 glycoproteins for SARS-CoV-2 (Covid-19) in response to urgent demand. These reagents are suitable for use in basic research and the development of diagnostics and vaccines.These antigens have been...

Coronaviruses: The Next Disease X?

For much of their known history, the coronaviruses were regarded as relatively benign pathogens with little potential to cause human harm. However, the emergence of SARS and MERS in recent decades has brought coronaviruses into the global spotlight. In this blog we...