Pyrogens are biochemicals or microorganisms that are capable of causing fever in a patient. Many types of pyrogens exist and multiple detection systems are available..
A septic pyrogen is capable of causing infection, typically is a culturable bacterium, and is capable of being grown in culture.
An aseptic pyrogen produces fever yet cultures are negative.
Types of pyrogens:
(1) lipopolysaccharides from Gram-negative bacilli (endotoxins)
(2) exotoxins from Gram-positive bacteria
(3) other biochemical products (cell walls, etc)
(4) bacteria
(5) fungi
(6) viruses
(7) mycoplasma
Pyrogen Test |
Detects |
May Fail to Detect |
rabbit pyrogen test |
pyrogens capable of causing fever in rabbits |
very low concentration |
limulus amoebocyte lysate test |
lipopolysaccharides from Gram-negative bacteria |
any pyrogen that is not a lipopolysaccharide |
culture (bacteria, fungus, virus) |
intact micro-organisms |
nutritional or thermal requirements outside of culture settings |
gross inspection (turbidity, discoloration, bubbles, precipitate) |
proliferating organisms or incompatible chemicals |
low concentrations |
Specialty: Pharmacology, clinical