Some participants cheated by returning a pot full of water or supplying multiple samples, but a trial that paid young adult pharmacy customers $10 to provide a urine sample for chlamydia testing has been judged a success.
In 2011, six Canberra pharmacies took part in a trial aimed at increasing screening among sexually active young people for the infection, that often has no obvious symptoms but can cause infertility.
Eligible customers aged between 16 and 30 were give the opportunity to ''pee in a pot'' and be referred for treatment if they returned a positive result.
More than 970 samples were returned and 19 people tested positive for chlamydia, including two young women suspected of having pelvic inflammatory disease.
Chlamydia can be treated with antibiotics.
Unfortunately, some of those who tested positive to chlamydia failed to leave correct telephone details and could not be contacted.
Although a large number of samples were collected, 58 did not contain urine. Some clients put water or energy drinks in the sample pots. Some pots were returned empty.
Writing in the international journal Sexually Transmitted Infections, the project's co-ordinators also identified unauthorised repeat screening as a major problem.
Some young people provided samples on several occasions to multiple pharmacies, presumably to pocket extra cash. About two-thirds of participants were young men, a group with low levels of chlamydia testing.
Lead author Marian Currie, of Academic Unit of Medicine at the ANU, said the cash payments appeared to be a major contributor towards the higher number of men testing.
''This increased return rate suggests that the participants' cash reward was a major contributor to the success of our study. As with other chlamydia screening studies we have undertaken, the cash reward appears to have encouraged men to be screened,'' Dr Currie wrote.
The researchers recommended that chlamydia screening campaigns be conducted in pharmacies two or three times each year.
Dr Currie believed the $10 reward was a successful method for recruiting young people for screening.
''Despite the increasing use of financial incentives to encourage healthy or health-seeking behaviours, concerns about their use remain,'' she wrote.
''These centre on moral and ethical issues, such as a perception of coercion and bribery as well as cost-effectiveness. It can be argued that financial incentives are not bribes, but rather rewards for health-seeking behaviour.''
A broader three-year project offering $10 payments for chlamydia testing at events such as music festivals and Summernats, and on building sites and tertiary education campuses, has recently concluded after testing more than 5400 people.
Last year, more than 1200 cases of chlamydia were detected in the ACT.