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ID:589 Alcohol and acid fast bacilli (AAFB) culture - tissue or aspirate for TB
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DescriptionExtra pulmonary tuberculosis can present as "cold" abscesses in almost all sites. Lymphadenitis is the most common form of extra-pulmonary mycobacterial infection, any lymph node may be involved, although cervical lymph nodes are most commonly infected. Bone and joint, including spinal, tuberculosis is usually a result of haematogenous spread to the bone from a primary pulmonary infection. Abscesses should be aspirated using an aseptic technique. It is prudent to also request routine culture on samples from locations where bacterial infections are more common e.g. psoas and vertebral abscesses. Culture for AAFB in the laboratory uses continuous automated bacterial culture but can take up to 8 weeks. Further identification and susceptibility testing are provided following referral to Birmingham PHL laboratory (currently the referral lab is not accredited for this test)
Indication Suspected extra-pulmonary TB, Samples from normally sterile sites (such as pleural, cerebrospinal, pericardial, peritoneal, synovial fluids), tissue samples, skin samples and biopsies
Additional InfoPlease remember that tuberculosis is notifiable even on grounds of clinical suspicion alone. Selected patients might benefit from TB PCR which requires prior discussion with the microbiologist before testing.
Concurrent Testsna
Dietary Requirementsna
Interpretation Preliminary microscopy results will be reported negative or positive with a quantitative indication. Initial culture results will be reported as AAFB isolated with confirmation of final identification and sensitivities reported later.

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Collection ConditionsAspiration or tissue sampling using a sterile technique. For fluids send as large a volume as possible (max 20mls) If visualised, select a caseous portion of tissue for sampling. Appropriate infection control measures should be taken when obtaining samples to minimise aerosolisation of M. tuberculosis organisms and transmission to attending personnel. Specimens must not be placed in formalin or any other preservative, but collected aseptically and sent in a sterile dry container. If the volume of specimen is very small, and there is concern that it may dry out, then add a small amount of sterile saline (<5ml). Please request clearly AAFB culture and microscopy on form. Samples should be marked as Danger of Infection. Do not send samples for AAFB via the airtube.
Min. Vol Fluids min 2ml

Ref. Range (Male)
Ref. Range (Female)
Ref. Range (Paed)
Ref. Range Notes
Units - Not Defined -
IP Acute TATSee Turnaround Comment
IP Routine TATSee Turnaround Comment
GP Acute TATSee Turnaround Comment
GP Routine TATSee Turnaround Comment
Turnround CommentMicroscopy for AAFB will be available within 24 hours for samples received Monday to Friday before 12pm. Microscopy TAT for samples received at weekends and bank holidays will be 3 days. Culture 60 days Turnaround time may be increased if prolonged incubation is clinically indicated.

Originally edited by : Dr. H. Schuster. Review due on 30/11/2018 12:44:26. Published By K Roberts on 30/11/2017 12:44:26.