New molecular diagnostic tests for TB: Do patients benefit?. HSRC Roundtable 02 June 2014 Pren Naidoo Rory Dunbar, Elizabeth Du Toit, Margaret van Niekerk, Carl Lombard, Judy Caldwell, Nulda Beyers. Background. Key TB Challenges MDR-TB Estimated global cases (2012): 450,000
New molecular diagnostic tests for TB: Do patients benefit?
02 June 2014
Rory Dunbar, Elizabeth Du Toit, Margaret van Niekerk,
Carl Lombard, Judy Caldwell, Nulda Beyers
From:Beyond accuracy: creating acomprehensive evidence base for TB diagnostic toolsMann G et al; Int J Tuberc Lung Dis 2010;14:1518-24.
Universal Algorithm: Xpert MTB/RIF™ replaced smear
All presumptive TB cases 2 sputa submitted
Specimen 1Specimen 2
XpertNegative Culture if HIV+
Discard if HIV-/unknown
MTB+, Rif sensitiveSmear
MTB+, Rif resistantSmear, culture, LPA and 2nd line DST
Smear if only 1 sputum sample submitted
Targeted Algorithm: Smear/Culture/DST (LPA)
Low MDR-risk2 sputa for smears (3rd for culture if Sm-, HIV+)
High MDR-risk2 sputa for smears, Culture, LPA DST
Are More TB Cases Diagnosed?
Are More MDR-TB Cases Diagnosed?
Total 188 Cases
Total 196 Cases
Group 1 and Group 2 – Smear/Culture
Group 1 - Xpert Group 2 – Smear/Culture
Do Patients Commence MDR-TB Rx Earlier?
MDR-TB Treatment Commencement Time (TCT)
Laboratory Turn Around Time (TAT)
MDR-TB TCT by HIV Status
MDR-TB TCT by MDR-Risk Profile
HIV+: HR 3.3 (95% CI 0.4 - 1.0)
p = 0.037
Low risk: HR 3.3 (95% CI:2.4-4.5)
High risk: HR 2.0 (95% CI:1.4-2.8)
*Calculated from first health care visit to any provider for current illness to MDR-TB treatment commencement
No increase in yield for TB / MDR-TB cases
25-day reduction in MDR-TB TCT
Substantial increase in laboratory costs
Cost saving for MDR-TB patients
Both patient and health system factors contribute to delay
New technology on its own does not suffice
Need to strengthen health systems and address patient factors to optimise test benefits
Cape Town Health Directorate Western Cape Provincial Department of Health National Health Laboratory Services
This research was supported by a United States Agency for International Development (USAID) Cooperative Agreement (TREAT TB – Agreement No. GHN-A-00-08-00004-00). The contents are the responsibility of the authors and do not necessarily reflect the views of USAID.