I wanted to share our recently accepted manuscript describing the yield and efficiency of 6 ICF algorithms: symptom- or C-reactive protein (CRP)-based TB screening, combined with confirmatory TB testing strategies inclusive of urine LAM, sputum Xpert and/or sputum culture. Below is the abstract and manuscript attachment (journal link: https://www.atsjournals.org/doi/abs/10.1164/rccm.201803-0490OC).
We invite your comments/concerns regarding ICF algorithms that replace symptom screening with CRP and the addition of urine LAM and culture to Xpert, considerations for other settings/populations, etc.
Rationale/Objectives: The recommended tuberculosis (TB) intensified case finding (ICF) algorithm for people living with HIV (PLHIV) – symptom-based screening followed by Xpert MTB/RIF (Xpert) testing – is insufficiently sensitive and results in unnecessary Xpert testing. We evaluated whether novel ICF algorithms combining C-reactive protein (CRP)-based screening with urine Determine TB-LAM (TB-LAM), sputum Xpert and/or sputum culture could improve ICF yield and efficiency.
Methods/Measurements: We compared the yield and efficiency of novel ICF algorithms inclusive of POC CRP-based TB screening and confirmatory testing with urine TB-LAM (if CD4 count ≤100 cells/μL), sputum Xpert, and/or a single sputum culture among consecutive PLHIV with CD4 counts ≤350 cells/uL initiating antiretroviral therapy in Uganda.
Main Results: Of 1245 PLHIV, 203 (16%) had culture-confirmed TB including 101 (49%) patients with CD4 counts ≤100 cells/μL. Compared to the current ICF algorithm, POC CRP-based TB screening followed by Xpert testing had similar yield (56% [95% CI: 49-63] vs. 59% [95% CI: 51-65]) but consumed less than half as many Xpert assays per TB case detected (9 vs. 4). Addition of TB-LAM did not significantly increase diagnostic yield relative to the current ICF algorithm but provided same-day diagnosis for 26% of TB patients with advanced HIV. Addition of a single culture to TB-LAM and Xpert substantially improved ICF yield, identifying 78% of all TB cases.
Conclusions: POC CRP-based screening can improve ICF efficiency among PLHIV. Addition of TB-LAM and a single culture to Xpert confirmatory testing could enable HIV programs to increase the speed of TB diagnosis and ICF yield.