Costs of novel tuberculosis diagnostics--will countries be able to afford it?

Four priority target product profiles for the development of diagnostic tests for tuberculosis were identified: 1) Rapid sputum-based (RSP), 2) non-sputum Biomarker-based (BMT), 3) triage test followed by confirmatory test (TT), and 4) drug-susceptibility testing (DST). We assessed the cost of the new tests in suitable strategies and of the conventional diagnosis of tuberculosis as per World Health Organization guidelines, in 36 high tuberculosis and MDR burden countries. Costs were then compared to the available funding for tuberculosis at country level. Costs of diagnosing tuberculosis using RSP ranged US$93-187 million/year; if RSP unit cost is of US$2-4 it would be lower/similar cost than conventional strategy with sputum smear microscopy (US$ 119 million/year). Using BMT (with unit cost of US$2-4) would cost US$70-121 million/year and be lower/comparable cost than conventional diagnostics. Using TT with TPP characteristics (unit cost of US$1-2) followed by Xpert would reduce diagnostic costs up to US$36 million/year. Costs of using different novel DST strategies for the diagnosis of drug resistance would be higher compared with conventional diagnosis. Introducing a TT or a biomarker test with optimal characteristics would be affordable from a cost and affordability perspective at the current available funding for tuberculosis. Additional domestic or donor funding would be needed in most countries to achieve affordability for other new diagnostic tests.