Limulus Amebocyte Lysate (LAL) is a reagent used to detect bacterial endotoxins in pharmaceutical products, medical devices, radiopharmaceuticals, dialysis solutions, raw materials, in process samples, and water. Every LAL manufacturer holds a Biological License (BLA), which is provided by the United States Food and Drug Administration (FDA). A Biological License is an FDA regulatory process to ensure the safety and quality of medical devices and injectable drugs that contact human blood and spinal fluid. The filing process involves manufacturers submitting data and documentation that demonstrate the test methods specificity, sensitivity, accuracy, and reproducibility to the FDA for review to demonstrate the effectiveness and safety of LAL as a test method. Once a manufacturer has obtained a BLA, they must continue to maintain compliance with FDA regulations which includes reporting of quality results and frequent audits of the manufacturing process. LAL manufacturers must print their license number on each licensed product label.
The product insert, which accompanies the LAL product, is regulated under the FDA BLA and provides details on instructions for handling and usage, storage conditions, safety precautions, limitations, warnings, and other relevant information for use. Off-label usage, including utilizing any other volume, would be outside of current FDA licensing. It’s critical that users thoroughly read and understand the intended use and instructions to remain compliant.
The harmonized pharmacopoeia for the Bacterial Endotoxin Test including the United States Pharmacopoeia (USP), the European Pharmacopoeia (EP), and the Japanese Pharmacopoeia (JP) do not specify LAL reconstitution volumes or ratios for testing, but each state that the LAL manufacturers product insert must be followed for intended use as follows:
USP <85>1 Photometric Quantitative Techniques:
EP 2.6.142 Photometric Quantitative Techniques (Methods C, D, E, and F):
The end user must follow the manufacturers product insert to ensure compliance with both the FDA and the Harmonized Pharmacopoeia. For Charles River, our LAL product inserts state to use the lysate at 100 µl lysate to 100 µl sample but other LAL manufacturers may vary. If a user wishes to deviate from what is listed in the product insert, they must validate the deviation fully by following an alternate method validation on the lysate to ensure comparability and submitting all relevant data to the competent regulatory authority before using the altered method in routine use.
There has been much discussion about using LAL at different lysate/volume ratios. Charles River LAL is only validated under our BLA at the 100 µl lysate:100 µl of sample ratio and, as discussed above, it is not advisable to use any other ratio without performing alternate method validation. If this extra validation is not performed, the user would be using the LAL off label from the BLA, and this could lead to considerable ramifications from a regulatory perspective.
Charles River Endosafe® LAL Cartridges utilize a substantially smaller volume of LAL to sample and have been validated for use as per the expectations from the FDA and submitted all relevant data under our BLA. The cartridges are accepted by the FDA for routine use in bacterial endotoxin testing. Charles River cartridges offer rapid, easy to use testing, in addition to utilizing 95% less LAL than a standard microplate or gel-clot method, providing users a sustainable LAL test method.
It’s imperative that the end-users of an FDA licensed product understand and comply with the manufacturer’s product insert and recommendations. If you have any questions, you can reach out to your local LAL experts to discuss further.
1. United States Pharmacopoeia 44 2021, chapter <85> Bacterial Endotoxin Test
2. European Pharmacopoeia (Ph. Eur.) 11th Edition, chapter 2.6.14 Bacterial Endotoxins
Author: Nicola Swift Reid, Associate Director Product Management, Endotoxin Products at Charles River Laboratories