Factors You Need to Consider For Proper Bacterial Endotoxin Testing

Proper bacterial endotoxin testing requires careful attention to various considerations to ensure accurate and reliable results. These considerations include:

1. Method Selection: It is important to choose an appropriate endotoxin detection method based on the sample matrix, sensitivity requirements, and regulatory guidelines. The most common methods include the gel-clot, turbidimetric, and chromogenic assays.
2. Method Development, Validation & Verification: Next it is important to validate and verify the chosen endotoxin testing method to ensure its suitability for the intended purpose. This involves demonstrating the method’s accuracy, precision, specificity, and robustness. Method verification is performed when we look to confirm the general method works with a specific product, but do not intend to write a specific SOP (Standard Operating Procedure) for that sample, typically for less intensive tests such as water activity.
3. Control of Interfering Factors: Sometimes factors present in the sample matrix can interfere with the endotoxin detection assay, leading to false results. Adequate sample preparation techniques, such as dilution, suspension, neutralization, filtration, or extraction, may be necessary to remove or minimize interfering factors. At NJ Labs, we resuspend every powder into solution and neutralize any acids or bases to achieve a more neutral pH level.
4. Reference Standards: It is important to choose a lab that uses appropriate endotoxin reference standards. At NJ Labs, we calibrate using the Control Standard Endotoxin (CSE), the same strain used in the Reference Standard Endotoxin by the USP and EP. These standards provide a known concentration of endotoxins for accurate calibration and quantification. We also follow USP <85> guidelines and our SOPs reflect that.
5. Quality Control: It is important that the testing lab has a comprehensive quality control program to monitor the performance of the endotoxin testing process. This includes regular testing of positive and negative controls, monitoring equipment calibration and maintenance, and adherence to good laboratory practices. NJ Labs is FDA & DEA registered, ISO 17025: 2017 certified and also follows CGMP practices.
6. Sample Handling and Storage: It is important to properly handle and store samples to prevent contamination or degradation of endotoxins. Use of aseptic techniques including suitable containers and appropriate storage conditions will help to maintain sample integrity. We also believe it is important to use pyrogen-free reagents, such as tubes and tips, as those are crucial for not introducing endotoxin contamination.
7. Endotoxin Limits: It is important for a testing lab to understand and comply with the regulatory requirements and guidelines regarding acceptable endotoxin limits for different types of products. These limits are usually specified by regulatory bodies such as the USP, EP, or other applicable pharmacopeia reference standards.
8. Training and Expertise: It goes without saying that the lab personnel involved in endotoxin testing are adequately trained in the testing methods, procedures, and relevant regulations. Ongoing training and competency assessment are essential to maintain accurate and reliable results.
9. Data Integrity: Maintaining accurate and complete records of all endotoxin testing activities, including sample information, test results, calculations, and any deviations or investigations is critical to testing integrity. 21 CFR Part 11 also stipulates software requirements that any competent lab should adhere to, ensuring traceability, reliability, and integrity of the data generated.
10. Compliance with Regulatory Requirements: Finally, it is important for a testing lab to stay updated with the latest regulatory requirements and guidelines related to endotoxin testing. A regular review should be conducted in order to revise procedures and protocols to align with current regulatory expectations.

We hope that these factors and best practices will help you when considering which laboratories can conduct endotoxin testing in a controlled and reliable manner, ensuring the safety and quality of pharmaceutical products and medical devices.