/hospitals in the Merseyside, Lancashire and Cumbria regions has some pleasing aspects;
• Total number of laboratories in the region=15.
• Number of responses received =13
IV. Diagnosis of latent TB
1. Mantoux testing should be performed.
2. Interferon-gamma (IFN γ)– tests, if available, should be considered for those in whom Mantoux testing is positive or is less reliable.
FindingsType of tests, Number of labs
Mantoux test = 7
Quantiferon test = 7
T-spot test = 2
Mantoux and IFNγ tests = 5**when chemoprophylaxis is indicated
Situations where IFNγ tests are recommended or performed, Number of labs
As evidence of exposure during a contact tracing exercise = 7
Diagnose latent TB in HCWs = 6
To rule out active TB as a possibility in smear negative cases = 2
To diagnose current active TB in smear negative cases = 2
Others = *
*Immunocompromised children, prior to start of immunosuppresive therapy, diagnose latent TB in immigrants.
IV. Diagnosis of latent tuberculosis
a. Increasing trend for the use of IFN-γ for a variety of situations.
b. 2 hospitals use it for diagnosis of active tuberculosis.
Agreed actions
NICE guidelines have considered the role of IFN-γ assays in the diagnosis of latent TB and have suggested its potential role in ruling out mycobacterial infection. Recent interim HPA guidance has also outlined certain situations when these assays can be performed, including diagnosis of active TB in exceptional circumstances.3 Hence, it was agreed that, in addition to having a regional centre, locally approved protocols would help streamline requests for IFN- γ testing, effecting better use of resources.
Conclusion
There is variable compliance with the NICE guidelines in the region. The only area where serious non-compliance was noted was in infection prevention and control of TB in hospitals, which will be addressed locally in each trust. The implementation will occur as soon as possible and will be undertaken by the respective Infection control teams. With respect to lab diagnosis including use of IFN-γ assays and molecular diagnostics, the protocols of testing have been adapted to suit the region, taking into account the incidence and prevalence of TB. However, there is need for optimum utilisation of resources and it was agreed that a locally approved protocol and a centralised service would be a best way forward, although a timescale would be difficult to predict. A re-audit has been planned in a year’s time unless an update to the guidelines is issued earlier.
