What is an Endotoxin Test?

An endotoxin test is a lab test to check for the presence of endotoxins like lipopolysaccharide in a sample. Endotoxins are chemical compounds, made primarily by Gram negative bacteria. They can be very dangerous to humans, leading to health conditions like septic shock if they enter the bloodstream. Manufacturers of drugs and medical devices use endotoxin testing in quality control to make sure their products are pure and safe for use. This testing can also be useful for labs concerned about contamination of samples used in research.

The classic endotoxin test relies on a compound found in the blood of horseshoe crabs. This compound causes clotting when endotoxins are present. Manufacturers harvest blood from horseshoe crabs to provide a steady supply for endotoxin test kits. A laboratory technician can run a variety of types of test using this compound to see if there are endotoxins in a sample and to determine their concentrations.

When medications or devices are contaminated with endotoxins, this can expose patients to risk. People who are already sick may be less able to metabolize the toxin, and could become seriously ill if they take contaminated drugs or use contaminated devices. Manufacturers and other facilities perform regular endotoxin testing to look for signs of contamination. If the endotoxin test reveals a problem, the manufacturer can halt distribution of a lot, or recall it in cases where it is already on the market. The testing takes place on a regular basis along with other quality control measures for safety.

In research laboratories, endotoxin contamination is an ongoing issue. Many samples require treatment to remove endotoxins and an endotoxin test must verify the success of the treatment. People performing research with contaminated samples will not obtain reliable, repeatable, or useful results. In cases where contamination compromises an experiment, it can also be helpful to know more about the nature of the contamination and the source, as this can be useful for avoiding future problems and understanding the results of the experiment.

Many labs offer endotoxin test services to people who only need periodic testing. Other companies maintain their own facilities for testing. In all cases, very precise protocols determine how technicians perform the testing. People must log their activities and provide careful documentation. This allows for audits of testing practices in the event of a problem. In manufacturing facilities, safety inspectors can ask to review these records as part of a routine inspection to make sure the facility is complying with legal requirements.