BMC Public Health 2009, 9:100 http://www.biomedcentral.com/1471-2458/9/100 Table 1: Reported use of a self-test for 25 conditions, frequency of use and frequency of true home testing Self-tests number % of self-testers (n = 1263) number (%b) true home tests % of total (n = 7919) - diabetes - cholesterol - allergies - urinary infection - HIV infection - anaemia - ovulation - Chlamydia - glandular fever - hepatitis B/C - menopause/female fertility - syphilis - vaginal infection/Candida - kidney diseases - thyroid diseases - influenza - blood coagulation - fertility male - intestinal cancer - prostate cancer - test kit for specific diseasesa - general test kita - hereditary disease(s) - helicobacter pylori - lactose intolerance - gluten intolerance - loss of amniotic fluid 488 431 156 150 140 136 130 113 106 92 86 67 61 53 53 43 42 30 28 22 22 20 19 18 14 13 11 39 34 12 12 11 11 15* 9 8 7 10* 5 7* 4 4 3 3 8** 2 6** 2 2 2 1 1 1 1* 6.2 5.4 2.0 1.9 1.8 1.7 2.5* 1.4 1.3 1.2 1.7* 0.8 1.2* 0.7 0.7 0.5 0.5 1.1** 0.4 0.8** 0.3 0.3 0.2 0.2 0.2 0.2 0.2* 148 (30) 106 (25) 21 (14) 31 (21) 9 (6) 9 (7) 119 (92) 6 (5) 17 (16) 4 (4) 65 (76) 2 (3) 8 (13) 19 (36) 1 (2) 9 (21) 6 (14) 6 (20) 3 (11) 2 (9) 3 (16) 3 (21) 1 (7) 3 (17) 3 (21) 1 (8) 1 (9) * % of women ** % of men a multiple tests per kit b % of total number of respondents who reported to have used this specific self-test addition, female self-testers had a higher level of educa- tion and were more likely to be blood donors, whereas male self-testers were less likely to be physically active. Discussion We found that 16% of a sample of Internet users had ever used a self-test, with an average of 2.1 tests per self-tester. Seventeen percent of those who had never used a self-test reported that they probably or definitely would consider using one in the future. The top 10 of most frequently used tests included those for diabetes, cholesterol, aller- gies, urinary infection, HIV infection, anaemia, ovulation, Chlamydia, glandular fever and hepatitis B/C. Self-testers generally reported lower health status and had a higher BMI than non-testers. On the other hand (or conse- quently), they were more likely to engage in health- related behaviour such as the use of dietary supplements and homeopathic medicine. As far as we know, few results of comparable studies on this topic are currently available. A recently published study in the United Kingdom found that almost a third of the respondents had used a self-test, including pregnancy tests and blood pressure monitors. After the exclusion of these two tests, the most frequently reported self-test was that for diabetes [9]. Another study in the United King- dom, with aims similar to those of our study, is still in progress [2]. As mentioned in the introduction, it is quite possible that consumers with complaints refrain from seeking a doc- tor's advice in the case of false-negative test results, as well as in the case of true-negative results. We found no studies that had investigated consumers' follow-up behaviour based on the test result. A secondary analysis of a sub- group (n = 684) of self-testers in our study showed that almost one quarter had been confronted with a positive test result, resulting in 75% of them seeking a doctor's advice. Of those reporting a normal test result (72%), 9% reported a follow-up contact with a general practitioner [1]. However, it remains unclear whether there was prob- lematic follow-up behaviour based on the test results. The present study had several limitations. The generalisa- bility of our Internet sample is clearly an issue. First, our panel is not representative of the Dutch population. Com- Page 4 of 6 (page number not for citation purposes)