The statistics were drawn from a free HIV test and counselling session during a two-week pilot program in 2003.
The numbers which are as follows reveal that on charged days the cost was $170 to avert an HIV infection while it was $92 on free days.
People increased from 4.1 per day before the free testing interval to 15.0 per day during the pilot program.
There was a decrease to 7.1 people per day after the small fee - 1,000 Tanzania shillings or 95 U.S. cents - was reinstated.
The cost includes staff salaries, laboratory supplies and test kits, utilities and office supplies.
American Journal of Public Health journal of January 2006 has the study and results documented.
Funding was provided by Roche Laboratories; the National Institutes of Allergy and Infectious Diseases, part of the National Institutes of Health. The awards were from the U.S. Department of State Fulbright Program to Nathan Thielman and Helen Chu.
Thielman, an associate professor of infectious diseases and medicine at Duke University Medical Centre said, "I think there is an important policy message here. Providing free HIV tests increases the number of clients presenting for evaluation and makes HIV prevention more cost-effective. We changed our practice because of these results."
The NGO KIWAKKUKI, an acronym for the Swahili name of "Woman Against AIDS in Kilimanjaro, were partners with Duke University.
"It's amazing to me that the numbers are so high. The demand is there - people want to know if they are infected," said senior study author John Crump, M.D., a Duke assistant professor of medicine who works full-time at the Kilimanjaro Christian Medical Centre in Tanzania. "One reason is because there is much greater access now to antiretroviral therapy."
As stated by Thielman , "Cost is probably the biggest barrier, but if the goal is to prevent HIV infection, free HIV testing and counseling provides outstanding bang for your buck. "Right now there is a lot of emphasis on treatment, which is appropriate, but prevention is also important, and HIV testing clearly helps to avert HIV infections. For every $92 invested in free HIV testing and counselling at an organization such as KIWAKKUKI, an HIV infection can be averted."