TB Manual

A.2.1. Biosafety requirements

Microbiologic diagnosis of TB is obtained by the detection of MTBC organisms in clinical samples. The diagnostic approach varies from province to province and can include a combination of front-line labs in remote settings, more specialized hospital-based labs and provincial reference labs. Laboratories that perform culture amplification of human pathogens such as Mycobacterium tuberculosis (M. tuberculosis) must comply with the Human Pathogens and Toxins Act⁶² and the corresponding operational and physical biosafety requirements outlined in the Government of Canada’s Canadian Biosafety Standard (CBS) Guideline, Second Edition.⁶³ In these guidelines, M. tuberculosis is classified as a Risk Group 3 pathogen, for which biosafety Containment Level (CL) 3 is required for propagative activities. However, certain diagnostic activities can be conducted safely at CL2, as specified in the new MTBC Biosafety Directive.⁶⁴ This directive is to be used in conjunction with the CBS Guideline to ensure safety of laboratory personnel conducting M. tuberculosis diagnostic activities

A.2.2. Receiving and transporting specimens

Most specimens submitted for mycobacterial culture originate from the respiratory tract, but tissue, sterile body fluids, urine and gastric aspirates are also commonly submitted (see Chapter 3: Diagnosis of Tuberculosis Disease and Drug-resistant Tuberculosis and Chapter 7: Extra-pulmonary Tuberculosis). If a laboratory does not have processing facilities, specimens should be referred to a laboratory that does. Processing should be done within 24 hours of specimen collection to avoid overgrowth by other microorganisms or deterioration of the sample.²⁸ Specimens should be kept refrigerated at 4 °C (except blood culture and cerebrospinal fluid specimens) if not transported immediately.

All types of clinical specimens are potentially contagious and therefore should be handled with the same procedures. Laboratories are required to adhere to the Transportation of Dangerous Goods Act (Canada) and the International Air Transport Association’s Dangerous Goods Regulations (for transport by air) when transporting clinical specimens or cultures to another facility. The accepting facility is required to accept and process the incoming specimens according to the relevant acts and regulations. The most current information on Transport of Dangerous Goods is available through the Government of Canada website.⁶⁵

A.2.3. Quality assurance and proficiency testing

All laboratories should be accredited by a recognized national/international accrediting organization and should participate in internal and external quality assurance/quality control activities in conjunction with a reference laboratory. These programs will assess the reproducibility and the inter-laboratory variability of the methods used and adherence to standardized testing procedures. For peripheral labs performing nucleic acid amplification tests (NAAT) in remote Canadian settings, quality assurance can be achieved under the oversight of an accredited clinical mycobacteriology laboratory, to ensure expected results with control samples and to cross-validate NAAT results with other results obtained from the same specimens.