What are the costs of suspected but not reported tuberculosis?

Little is known regarding patients suspected, but not proven, to have tuberculosis before meeting reporting requirements. These patients generate unmeasured tuberculosis costs to the health care system. Elimination efforts are undervalued without fully quantifying the burden of tuberculosis. This may lead to decreased support and resurgence of this disease. This report provides a preliminary quantification of these costs.

We used acid-fast bacillus (AFB) cultures completed as a proxy to estimate the number of patients with suspected tuberculosis who are never reported. We collected data on the number of AFB tests conducted in Tarrant County, TX, for calendar year 2002. We excluded all tests positive for Mycobacterium tuberculosis or secondary to growth of mycobacteria not M tuberculosis. We considered all AFBs conducted on an individual within 90 days to be single diagnostic episodes. We measured the number of diagnostic episodes, number of AFBs, number of AFBs meeting inclusion criteria, estimated cost incurred by testing, and individuals affected.

The Tarrant County hospitals sampled completed 6935 AFB cultures on an inpatient volume of 142,356 patients. One hundred ninety-three cultures confirmed tuberculosis or other mycobacteria, and 6742 AFBs were collected on persons suspected, but not proved, to have tuberculosis at an estimated $114.06 per culture. The total cost of eliminating tuberculosis as a cause of illness was $768,993. Laboratory costs for each patient with suspected, but not confirmed, tuberculosis averaged $364.11. One hundred forty-eight AFB cultures costing $16,830 were needed to confirm one case of tuberculosis.

The suspicion of tuberculosis incurs significant burdens and cost in the US health care system. More fully valuing tuberculosis elimination is important for tuberculosis management and will help maintain support for tuberculosis elimination.