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ID:583 Alcohol and acid fast bacilli (AAFB) culture - General Information
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Description85% of clinical tuberculosis cases present as pulmonary tuberculosis. Extrapulmonary tuberculosis can affect all organs with miliary tuberculosis and tuberculous meningitis being very serious disease presentations. Tuberculous lymphadenitis, abdominal tuberculosis, "cold" abscesses and skeletal tuberculosis are other sites. Latent tuberculosis denotes a condition when patients are infected with tuberculosis but show no clinical symptoms. Latently infected patients are not infectious to others but carry a 10% lifetime risk of developing active i.e. clinical TB with the highest risk of developing active disease within 2 years after becoming latently infected. Tuberculin skin testing (Mantoux testing) is the current diagnostic standard but gamma-interferon testing (Quantiferon-Gold)offers an alternative for selected patients.
Additional InfoAuramine staining of tissue samples is carried out within 24-48 hrs after receipt of samples but microscopy is less sensitive than culture. In selected patients TB PCR can be of value but this has to be discussed with a microbiologist prior to testing.
Concurrent Testsna
Dietary Requirementsna
InterpretationPreliminary 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

Sample* Not Specified *
Tube Picture
Collection ConditionsSee specific tests and tubes entries for BAL, Sputum, Pus, CSF, Tissue & Blood Culture Other samples that may be collected include Gastric Aspirates: Usually only performed on either young children or occasionally elderly patients with dementia, who cannot expectorate sputum. Swabs: only consider if other samples are genuinely unobtainable as very low sensitivity. Faeces: present particular problems of bacterial contamination and they are not usually an appropriate specimen but they may be of use where disseminated mycobacterial disease is being considered in immunocompromised patients. . If a faeces sample appears to be clinically indicated, the request should usually be discussed with the laboratory prior to submitting the sample. The sample should be collected in a sterile, wax-free container. A “minimum” of 1g is required
Min. Vol See specific enteries
Freq.s. for specific sample/tissue type

Ref. Range (Male)
Ref. Range (Female)
Ref. Range (Paed)
Ref. Range Notes
Units - Not Defined -
IP Acute TAT60 days
IP Routine TAT60 days
GP Acute TAT60 days
GP Routine TAT60 days
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 12:24:26. Published By K Roberts on 30/11/2017 12:24:26.