NAAT Is it Time for a New Option in California?

Background CDC 2009 guidelines recommend NAAT for each patient with suspected TB for whom the test result would alter treatment or TB control activities Experience in several settings has found significant efficiencies with NAAT by reducing unnecessary –treatment –isolation –contact investigation

Challenges Test characteristics –limited sensitivity for smear negative –laboratory complexity (MTD) –variable performance (home brew) Availability Delay in results

GeneXpert (Cepheid) New platform for TB NAAT Platform used for other diseases Technically simple Performance similar to MTD –very high specificity –very high sensitivity for smear positive –~75% sensitivity for smear negative Provides rapid rifampin susceptibility FDA approval possible

Luke Davis. MD Under-treatment is rare in SFDPH TB Clinic… 426 TB suspects (TB5) in (15%) TB3 –Only 2 (3%) not started on empiric treatment

Luke Davis. MD …Over-treatment is common in SFDPH TB Clinic 109/426 TB5s were treated –46/109 (42%) did not have TB 31 (29%) received unnecessary DOT Median 47 days of unnecessary treatment 29/63 (46%) contact investigations initiated unnecessarily –87/321 (27%) “case” contacts unnecessarily identified

Luke Davis. MD TB GeneXpert Protocol at SFDPH Included –Pulmonary TB Suspect High/Moderate starting TB treatment –Pulmonary TB Suspect Low in congregate housing Excluded –Prior TB treatment within last 12 months Procedures –Sputum x 3 for routine AFB smear/culture –Sputum x 1 for TB GeneXpert Testing –Performed at SFDPH 2-3 days week, results within 1-2 days Monthly follow-up until confirmed final diagnosis if treatment held

Luke Davis. MD 15 High & Moderate TB Suspects on Treatment Xpert changed treatment in 9 –4 AFB+, Xpert+  M. TB, empiric treatment continued –1 AFB+, Xpert-  M. kansasii, empiric treatment changed –10 AFB-, Xpert- 8 empiric treatments changed –6 TB0  Stopped when Xpert- –2 TB4  Tailored to INH+RIF for TB4 2 empiric treatments continued –1 TB0  Stopped after 2 months –1 TB3  Continued when BAL + Contact investigation suspended in all 11 Xpert- –In 1 AFB-, BAL MTB+ patient, contact investigation started later

Luke Davis. MD 4 TB5 Low 3 not on treatment –All AFB-, Xpert- Sent to MH/SA programs 1 on treatment –AFB-, Xpert- Treatment discontinued Sent to MH/SA program TB controllers How birds see the world

Why Now? APHL/CDC funding opportunity for equipment and supply purchase New system with better characteristics Importance of efficiency in current resource setting Continued requests for NAAT

Options Local public health labs could implement— likely not feasible for all Some hospitals may offer—availability unclear CDPH could implement, either at state or a local lab

State Option GeneXpert system –rapid diagnosis of M. tb complex (NAAT) –expanded rapid rifampin resistance testing Follow up culture and DST Prepaid shipping contract

What Will it Take? Funds available for initial investment Recurrent costs (staff, supplies, shipping): $215,000/year Some funds may come from other sources –CDCR? –CDC? Balance from local assistance/detention –used for emergency funding requests

Discussion