Self-tests
Another big topic related to new IVDDs is usage of self-tests (ST). There are several risks associated with them13:
Diagnostic sensitivity
False-negatives are cases when device shows negative result, though the true result should be positive. Since self-testers often perform tests for reassurance, without considering the disadvantages12, in the best case self-tests for high severity conditions should be available only if false-negative ratio is in the similar range as for clinical tests. Otherwise poorly informed patient may be harmed in case of false-negative; treatment will postpone and condition worsen. Consumer information should promote more informed usage for self-testing12.
False-positives are cases when device shows positive result, though the true result should be negative. Though this fault may seem to be less harmful, since in case of testing for severe disease like HIV most of patients are aware that positive result must be confirmed3, in case of testing for milder conditions, patient may receive unnecessary and potentially harmful treatment.
Analytical sensitivity
False-negative between infection and seroconversion: this risk is related rather to immunoassays and is less relevant for tests like our which is based on detection of nucleic acids.
Accuracy
Deciding for accuracy are the performance of the test and ability of inexperienced person to properly use it13. While the performance is a subject of regulation, it was shown that some devices fail to deliver clear complete usage instructions13. But even provided instructions are not always followed by all the users13. There are contradictiory results provided regarding this aspect, for example a review of studies on usage of HIV self-tests showed that most participants properly performed home tests and obtained accurate results3. The same review suggests people often had trouble performing blood-based tests. On the other hand result of a study among young adults suggests that many of them did not follow all instructions while performing the test for such severe condition as HIV infection4.
A poorly functioning home test may harm credibility in the reliability of rapid tests generally and, for example, weaken efforts to expand HIV detection2.
Absence of professional counseling
In case of self-test user does not get immediate counseling from health professional, which may cause possible delayed entry to care11. Currently available HIV self-tests have limited follow-up options, for example, in U.S. they mostly provide only phone number that participant may call8. Rather governmental programs of follow-up counseling are required with clear instructions of acting in case of positive test. This study also points out that self-tests also fails to guide users whose tests are negative to prevention services so that they can reduce their future risk for HIV infection8. As a possible solution self-test devices may be equipped with an Internet of Things module reporting the case with delivery of timely, active follow-up counseling and referrals over the phone8.
Some of users may initiate self-treatment based on results they found on Internet, which may be misleading and harmful for their health.
Wrong interpretation of results by badly informed user may cause interrupt of treatment or change of dosages of taken mediacations.
Facing positive result for severe condition
Positive result for severe disease may have an effect on emotional and psychological condition of user. Before making self-tests for many diseases available to general public, this effect must be studied more thoroughly.
Overall effect on public health
There are not many studies conducted yet since there are self-test for few specific conditions available on the market until now and effect of ability to test yourself for everything is not known. Before the introduction of self-test for HIV, mathematical model in one study prognosed increase in HIV among men having sex with men, even if home-use tests will cause overall testing6.
Another concern is not reaching the target group. Before first HIV ST was permitted in the U.S., some experts expected that test will be mostly used by wealthy HIV-uninfected people, so that it will not fulfill its goal to help infected people to discover their condition2. Their study suggested test may have the perverse effect of false-positive and false-negative results. On the other hand, it was shown in another study that self-test usage in Netherlands was higher among high-risk individuals7.
Probably not all the users who were tested positive for severe condition will ask for professional medical counseling, even if it’s available. Some diseases currently must be reported to epidemiology and infectious disease control centers to enable disease monitoring and epidemy prevention. In case of unreported self-positive epidemy may be overseen. This may be sollved by IoT module8, but limits usage of device because of higher price.
Coercion
Another concern regarding self-tests is coercion11, since it allows someone to force test usage. It may be especially the case for stigmatized conditions like HIV infection.
Counterfeit
Counterfeit self-tests which are providing false results to users may have huge effect on individual and public health. Strict regulation of tests market and informing of potential users about trusted sources of tests is crucial especially in less-developed countries.
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