Mycobacterial and respiratory investigation

Housed in our state of the art containment level 3 laboratories, the CL3 service offers a comprehensive Mycobacterial diagnostics service.

Our service includes auramine smear microscopy, with a 24-hour turnaround from the time the sample arrives at the Halo, and rapid PCR testing to detect M. tuberculosis complex and Rifampicin resistance. 

The mainstay of detection is mycobacterial culture, from specimens including blood, tissue, early morning urine (EMU; minimum 60ml) and respiratory samples. Mycobacteria isolates are first examined with MPT64 rapid antigen testing for the preliminary identification of MTB; Isolates are then referred to the Mycobacterial Reference Laboratory (MRL) for full identification and susceptibility testing.

The routine culture of specimens for Mycobacterium species is primarily carried out through MGIT liquid broth automated culture. After careful clinical review the laboratory service has discontinued Löwenstein–Jensen (LJ) agar slope for routine culture.

The following lists detail the specimens which will have a LJ agar slope culture carried out in addition to the routine MGIT liquid broth automated culture: 

• Supplementary LJ slope culture at 30°C, incubated for 8 weeks:
  • All skin biopsies
  • Any specimen where clinical details indicate possible M. marinum infection 
• Supplementary LJ slope culture at 37°C, incubated for 8 weeks:
  • Any specimen which is positive on Mycobacterium tuberculosis PCR direct from specimen
  • Any specimen which is positive on auramine stain direct from specimen
  • All lung and pleural biopsies
  • On clinical request via laboratory communication or through clinical details provided with the specimen. For LJ slopes to be set up, the request needs to specify the clinical reasons why extended Mycobacterial culture is required.

Negative mycobacterial cultures are reported after 6-weeks incubation. Routine respiratory culture is performed for the detection of respiratory pathogens, and PCR for the investigation of atypical Pathogens (Legionella pneumophila, Mycoplasma pneumoniae and Chlamydia pneumoniae) is available.

If you wish to contact the laboratory to request supplementary LJ slope culture at 37°C, please telephone 0203 908 1390 or email Mycobacteria@hslpathology.com.