The key difference between LAL test and pyrogen test is that the LAL test is designed to detect bacterial endotoxins or pyrogens derived exclusively from Gram-negative bacteria in drugs and biological products, while the pyrogen test is intended to identify both bacterial endotoxins (pyrogens) and non-endotoxins pyrogens in drugs and biological products.
Testing for pyrogens, including bacterial endotoxins and non-endotoxin pyrogens, is an imperative safety metric for the regulatory approval of medical devices or products. These tests ensure that medical devices and products are free of pyrogenic endotoxins, thereby minimizing the risk of pyogenesis or infection following device or product use. The Limulus amoebocyte lysate (LAL) test and the pyrogen test are two highly popular methods for detecting pyrogens in drugs and biological products within the pharmaceutical industry and medicine. However, the LAL test is more sensitive, requires fewer samples, can be completed in less than 1 hour, and is significantly less expensive than the pyrogen test (whether the rabbit pyrogen test or in vitro pyrogen test).
CONTENTS
1. Overview and Key Difference
2. What is the LAL Test (Limulus Amoebocyte Lysate Test)
3. What is the Pyrogen Test
4. Similarities – LAL Test and Pyrogen Test
5. LAL Test vs. Pyrogen Test in Tabular Form
6. FAQ – LAL Test and Pyrogen Test
7. Summary – LAL Test vs. Pyrogen Test
What is the LAL Test (Limulus Amoebocyte Lysate Test)?
Frederick Bang and Jack Levin observed amoebocytes of the horseshoe crab (Limulus polyphemus) clot when exposed to endotoxins in the 1950s. Based on this, the LAL test was developed later across pharmacological industries as an endotoxin detection assay. It is a bacterial endotoxin test employed by medicinal product manufacturers worldwide. In some instances, the LAL test not only detects the presence of endotoxins but also allows for the quantification of these endotoxins, specifically lipopolysaccharides (LPS) originating from gram-negative bacteria.
Figure 01: LAL Test
There are different variations in this test, such as gel clot LAL test assay, turbidimetric LAL test assay, and chromogenic LAL test assay. Though the LAL test is more sensitive, requires fewer samples, can be completed in less than 1 hour, and is much less expensive than the pyrogen test, it fails to detect non-endotoxin pyrogens that derive from gram-positive bacteria, plastics, molds, and a wide host of other sources.
What is the Pyrogen Test?
The pyrogen test determines the presence or absence of pyrogens, encompassing both bacterial endotoxins and non-endotoxin pyrogens, in parenteral pharmaceutical products. Pyrogen test is regulated by several standards from authorities such as the Food and Drug Administration (FDA), United States Pharmacopeia (USP), and European Pharmacopeia (EP).
Pyrogen tests can be performed in both in vitro and in vivo conditions. One of the advantages of this test is it covers all available pyrogens detection. However, this test is high cost, consumes a lot of time, and needs animal experiments.
What are the Similarities Between LAL Test and Pyrogen Test?
- LAL test and pyrogen test are two very popular tests that detect pyrogens in drugs and biological products of the pharmaceutical industry and medicine.
- Bacterial endotoxin pyogenes can be detected by both tests.
- Both tests can be performed under in vitro
- Both tests have advantages as well as disadvantages.
What is the Difference Between LAL Test and Pyrogen Test?
LAL test is designed to detect bacterial endotoxins or pyrogens derived exclusively from Gram-negative bacteria in drugs and biological products, while the pyrogen test is intended to identify both bacterial endotoxins (pyrogens) and non-endotoxins pyrogens in drugs and biological products. Thus, this is the key difference between LAL test and pyrogen test. Furthermore, the LAL test is only performed in vitro conditions, while the pyrogen test can be performed in both in vitro and in vivo conditions.
The infographic below presents the differences between LAL test and pyrogen test in tabular form for side-by-side comparison.
FAQ: LAL Test and Pyrogen Test
What is the principle of the LAL test for pyrogen testing?
The principle of the LAL test is a reaction between LPS and a substance (clottable protein) contained within amoebocyte cells derived from the blood of the horseshoe crab.
What is the pyrogen test used for?
Pyrogen test is used to determine the presence or absence of pyrogens in parenteral pharmaceutical products
What is the relationship between endotoxin and pyrogen?
Endotoxins are a type of pyrogen which are lipopolysaccharides.
Summary – LAL Test vs. Pyrogen Test
LAL test and pyrogen test are two very popular tests that detect pyrogens in drugs and biological products of the pharmaceutical industry and medicine. LAL test is a test to detect only bacterial endotoxin pyrogens derived from Gram-negative bacteria in drugs and biological products while pyrogen test is a test to detect both bacterial endotoxin pyrogens and non-endotoxin pyrogens in drugs and biological products. So, this summarizes the difference between LAL test and pyrogen test.
Reference:
1. Pusterla, Dr Tobias. “The Lal Assay: Detecting Bacterial Contamination.” The LAL Assay: Detecting Bacterial Contamination | BMG LABTECH, BMG LABTECH GmbH.
2.“Pyrogen Testing.” Sigmaaldrich.
Image Courtesy:
1. “LAL-D Diagnostic Pathway” By Alexion Pharmaceuiticals – (CC BY-SA 2.0) via Commons Wikimedia