LRN – HHS CDC manages the Laboratory Response Network (LRN).  This includes the CDC LRN-Biological (LRN-B) and CDC LRN-Chemical (LRN-C).  LRN-B presently has 157 member labs (two national laboratories and 155 reference laboratories). LRN-C has 55 member laboratories (ten Level 1 laboratories (these have the highest capability for detecting exposure to chemicals), 38 Level 2 laboratories, and 6 Level 3 laboratories).  The LRN was established pursuant to Presidential Decision Directive (PDD)-39.  It is a joint effort among HHS CDC, DoJ, FBI, the Association of Public Health Laboratories (APHL), and DoD.  The LRN became operational in October 1999.  The mission of the LRN is “to maintain an integrated national and international network of laboratories that are fully equipped to respond quickly to acts of chemical and biological terrorism, emerging infectious diseases, and other public health threats and emergencies.” For more information on the LRN, please visit: