Companies that test potential employees for their risk of developing carpal tunnel syndrome may be wasting their money, a new study suggests.

Researchers say the findings - based on more than 2,000 employees of an automobile-parts manufacturer - suggest that most companies that refuse to hire people who “fail” the test will end up hurting their bottom lines.

Carpal tunnel syndrome (CTS) is a disorder of the wrist and hand caused by pressure on the median nerve, which runs through a narrow passageway in the wrist - the carpal tunnel. Symptoms include pain, numbness and weakness in the hand, fingers and wrist.

Swelling in nearby tendons is often the source of pressure on the median nerve. Because certain jobs that put repetitive stress on the hand and wrist may lead to CTS, some companies screen prospective hires for their risk of the condition. Tests that measure how well nerve impulses travel through the carpal tunnel can spot people who are vulnerable to CTS.

It’s unclear how many U.S. companies use nerve testing to screen potential hires, but evidence suggests “it’s not rare,” Dr. Alfred Franzblau, the new study’s lead author, told Reuters Health.

Yet they’re apparently doing it without evidence that it actually saves them money, according to Franzblau, a professor at the University of Michigan School of Public Health in Ann Arbor.

In their study, reported in the Journal of Occupational and Environmental Medicine, he and his colleagues followed 2,150 employees at one company that tested for carpal tunnel risk as part of its “post-offer” medical exams. At the time the employees were hired - between 1996 and 2001 - the company was using nerve testing, but hiring workers regardless of the test results.

Franzblau’s team found that through May 2003, these employees made 35 workers’ compensation claims for carpal tunnel syndrome. And while the rate was higher among the 15 percent of workers who’d had abnormal nerve-test results, most CTS claims - 63 percent - came from employees who had tested normal.

Had the company refused to hire candidates with abnormal test results, the screening process would have cost it far more than it would have saved in workers’ comp and other costs, according to the study.

The researchers estimate that the company would have lost $357,353, once other factors, such as the cost of screening another several hundred applicants, were considered.

The findings further suggest that most companies would lose out financially, Franzblau said, because the study group had a “very high” rate of CTS claims - much higher than the typical company would see.

He and his colleagues note that the study looked only at the cost-effectiveness of not hiring people who fail nerve testing. It’s possible, but unproven, that the results would be different for companies that use the tests to place at-risk people in jobs that put less stress on the hand and wrist.

SOURCE: Journal of Occupational and Environmental Medicine, July 2004.