|Investigations||Microscopy for AFB
Culture and sensitivity of Mycobacteria species, including TB
|Inform lab before sending||No||Specimen type||
||Ideal time to take specimen||Before antimicrobial therapy where possible||Labelling requirements||click here||How to take the specimen||
Sputum & Bronchoalveolar lavage, (BAL's) 5 ml or greater :
3 fresh, purulent samples from the lower respiratory tract collected on consecutive days
3 fresh early morning samples (EMU) collected on consecutive days (mid-stream EMU are acceptable but full EMU samples are preferable).
CSF: 6ml (for adults) CSF in sterile leak proof container
Blood and Bone Marrow specimens must be inoculated into a specialised Mycobacteria blood & bone marrow culture bottle (contact the Bacteriology laboratory for bottles). Where possible it is recommended that blood culture bottles are inoculated at the bedside.
NOTE: If blood for other tests such as blood gases or ESR is to be taken at the same venepuncture, the blood culture bottles should be inoculated first to avoid contamination. It is preferable to take blood for culture separately, using aseptic technique, disinfect the skin at the venepuncture site using ethanol or isopropyl alcohol and allow to dry:
The following should be sent to the laboratory in a sterile leak proof container:
|Transport to the laboratory||
Send samples to laboratory via porter. Only in exceptional circumstances should these blood cultures be drawn outside normal laboratory hours.
Blood and bone marrow bottles: THESE ARE GLASS BOTTLES - DO NOT SEND TO LAB THROUGH POD SYSTEM.
|Test Times||Monday to Friday||Turnround||
Direct microscopy for AFB
Positive AFB smear to Direct MTB PCR result
Positive AFB smear to Culture result
Negative AFB smear to Culture result
Positive Culture to Gene Probe Identification
Positive Culture to full identification and antibiotic sensitivity result
|Additional information||If transport is delayed then refrigerate sample (not blood/bone marrow culture bottles, store these at room temperature). Delays of over 48 hours are undesirable Microscopy and culture for AFB are NOT routinely performed on all sputum samples received and the need for this investigation should be clearly marked on the request|
|Additional Examination Requests||Please ensure that any requests for additional investigations on the specimen are made within 7 days from the date of the original request|