摘要Background:A major impediment to the treatment of TB is a diagnostic process that requires multiple visits.Descriptions of patient costs associated with diagnosis use differentprotocols and are not comparable.Methods:We aimed to describe the direct costs incurred by adults attending TB diagnostic centres in four countries and factors associated with expenditure for diagnosis.Surveys of 2225 adults attending smear-microscopy centres in Nigeria,Nepal,Ethiopia and Yemen.Adults ＞18 years with cough ＞2 weeks were enrolled prospectively.Direct costs were quantified using structured questionnaires.Patients with costs ＞75th quartile were considered to have high expenditure (cases) and compared with patients with costs ＜75th quartile to identify factors associated with high expenditure.Results:The most significant expenses were due to clinic fees and transport.Most participants attended the centres with companions.High expenditure was associated with attending with company,residing in rural areas/other towns and illiteracy.Conclusions:The costs incurred by patients are substantial and share common patterns across countries.Removing user fees,transparent charging policies and reimbursing clinic expenses would reduce the poverty-inducing effects of direct diagnostic costs.In locations with limited resources,support could be prioritised for those most at risk of high expenditure;those who are illiterate,attend the service with company and rural residents.