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Laboratory Testing for Anthrax: Frequently Asked Questions

Which laboratories can test specimens for the bacteria that cause anthrax?

Laboratories that are a part of the Laboratory Response Network (LRN) can test patient specimens for Bacillus anthracis, the type of bacteria that causes anthrax.  LRN labs are strategically located across the United States and abroad, each playing a role in their state’s or territory’s overall emergency response plan.

The LRN links state and local public health laboratories with clinical, military, veterinary, and agricultural laboratories as well as laboratories that test water and food. Together, these laboratories can quickly identify biological threats, including anthrax:

  • Sentinel labs: Local clinical laboratories can conduct the preliminary tests of a specimen to rule out the presence of Bacillus anthracis. If the local clinical lab cannot rule this out (in other words, it looks like it might be anthrax), the specimen is sent to a reference lab.
  • Reference labs: Public health laboratories in state health departments and in large metropolitan areas can then verify whether the organism is B. anthracis. If it is, the specimens are sent to a national lab.
  • National labs: CDC labs, U.S. Army Medical Research Institute for Infectious Diseases (USAMRIID), and the Naval Medical Research Center (NMRC) can conduct more sophisticated tests to define the biological properties of this strain of B. anthracis. For example, they can determine whether the strain can be treated with antibiotics.

How does the LRN test for Bacillus anthracis?

  • If anthrax is not initially suspected in the sick patient, a specimen will be taken from the patient and cultured.  After the culture has had time to grow (from 12 to 36 hours up to 5 days), it will be tested to rule out if B. anthracis is present, using simple laboratory methods [PDF - 396 KB/22 pages] .
  • If anthrax is suspected in the patient, the specimen would be quickly sent to an LRN reference laboratory and a rapid method would be used to look for B. anthracis. The lab can test blood or other body fluids directly (this includes spinal fluid, sputum, and skin sore swabs) along with the culture and determine if B. anthracis is present using rapid laboratory tests such as real-time polymerase chain reaction (PCR).
  • If the lab finds B. anthracis in any of the specimens tested, it must be confirmed by a more definitive test. This test can be performed at a national or reference laboratory and can take 1-3 days for results.
  • If further characterization is needed, these tests take place at the national laboratories and can require a week or more for results.  


Can I be screened to find out whether I have been exposed to anthrax?

No.  There is no test a doctor can give you that determines if you have been exposed to anthrax.  The only way exposures can be determined is through a public health investigation. 

What role do labs play in an anthrax crisis?

If anthrax was intentionally released, quietly and without anyone knowing, it might be difficult for hospitals, doctors, and public health officials to diagnose anthrax in the first few patients. That’s why the Laboratory Response Network (LRN) would be essential during an anthrax emergency. Its purpose is to help hospitals, doctors, and public health officials quickly confirm a diagnosis of anthrax.

If patients are suspected as having anthrax, should they be quarantined?

No.  Anthrax is not contagious.  You cannot catch anthrax from another person the way you might catch a cold or the flu. In rare cases, person-to-person transmission has been reported with cutaneous anthrax, where discharges from skin lesions might be infectious.

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