Which test is used to detect pyrogenic responses using animals?

• A. LAL test
• B. Gel clot test
• C. Turbidimetric test
• D. Rabbit pyrogen test

Answer: (D)

Pyrogen testing is about detecting fever-inducing contaminants, so using a live animal model is one direct way to observe a true fever response. The rabbit pyrogen test is the method that uses animals for this purpose. In it, healthy rabbits receive the test sample and their rectal temperatures are watched for about three hours. If the rabbits show a fever that meets regulatory thresholds (commonly a mean rise around 0.5°C or more, or fever in the majority of animals), the batch is considered pyrogenic. This approach can detect a broad range of pyrogens beyond endotoxins, which is why it’s used when a broad pyrogen detection is needed. However, there are ethical concerns and many settings now favor non-animal, in vitro tests like the LAL-based assays (gel clot and turbidimetric) that detect endotoxins specifically.