|Description||TB meningitis (TBM) has to be considered in patients with a lymphocytic CSF pleocytosis and hypoglycorrhacia (NB requires plasma glucose taken at the time of the CSF glucose) For certain at risk populations TBM is high on the differential list but it is often forgotten in others. TB PCR can be considered for selected patients but the best diagnostic value is achieved when in excess of 10 mL CSF has been collected for TB PCR alone.
Initial indication of infection may be the identification of AAFB by microscopy. 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|| Diagnosis of TB meningitis|
|Additional Info|| Please 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 Tests||Plasma glucose & CSF glucose – separate fluoride bottles.|
|Interpretation|| Preliminary microscopy results will be reported negative or positive with a quantitative indication if sufficient sample.
Initial culture results will be reported as AAFB isolated with confirmation of final identification and sensitivities|
|Collection Conditions|| For CSF a single sample greater than 10ml can lead to increased yield. The likelihood of TB should be considered in the light of other results so it may be appropriate to request storage of a separate sample while awaiting other results before proceeding with AAFB investigations.|
|Min. Vol||2 mL|
|Ref. Range (Male)|| |
|Ref. Range (Female)|| |
|Ref. Range (Paed)|| |
|Ref. Range Notes||
|Units|| - Not Defined -|
|IP Acute TAT||See Turnaround Comment|
|IP Routine TAT||See Turnaround Comment|
|GP Acute TAT||See Turnaround Comment|
|GP Routine TAT||See Turnaround Comment|
|Turnround Comment||Microscopy 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 12:43:03. Published By K Roberts on 30/11/2017 12:43:03.