Laboratories and disease surveillance.

The U.S. communicable disease surveillance system depends on high-quality testing and reporting by clinical and public health laboratories (PHLs). Clinical laboratories offer a wide range of microbiological services, provide a large portion of all disease reports, and refer isolates and samples to PHLs for confirmation and typing. The PHLs support disease surveillance by providing special reference testing, serological or molecular typing to identify disease clusters and sources, primary laboratory services for high-risk clients, quality assurance and training for clinical laboratories, and testing for unique agents unavailable elsewhere. However, profound changes in the health care industry are threatening the ability of public- and private-sector laboratories to carry out disease surveillance activities. Isolates for typing and confirmation are less available, PHL surveillance testing volumes are lower, and relationships between clinical laboratories and PHLs have changed. The integrity of the U.S. disease control infrastructure depends on maintaining a complementary network of clinical and public health laboratories, and a national system for public health testing is needed.