Blood Tests

In connection with scientific projects, blood samples often need to be taken from participants. The following details central distinctions and damage minimization regarding blood sampling in research projects. There are, of course, differences depending on whether children or adults; sick or healthy individuals are involved with blood tests. Therefore, the following should always be seen in relation to a specific research project. However, all the mentioned considerations are relevant for all types of experiments where blood samples are taken.

What is the purpose?

Fundamentally, taking blood from research participants can serve two different purposes. Firstly, blood can be taken solely for the sake of the experiment’s results – i.e., blood samples that do not relate in any way to the participants' safety. This could be blood samples taken from healthy participants to establish the relevant baseline in a research project. Such samples can be called research-related blood samples. Secondly, blood samples in experiments can both address the experiment's results and the welfare or safety of the participants. For example, blood samples taken to monitor participants' health conditions. Such samples can be called safety-related blood samples. For participants, there is obviously not the same benefit from research-related as from safety-related blood samples. Therefore, more justification is needed for any risks to participants associated with research-related samples since they do not bring any immediate benefit to the participants themselves. Hence, in the ethical assessment, a distinction should (in principle) be made between blood samples taken solely for the project's results and blood samples taken out of consideration for participants' safety.

How important are the samples?

Blood samples can contribute more or less useful knowledge in connection with an experiment. For example, if the samples are used in connection with a primary endpoint, it speaks to the importance of the samples. It could be blood samples used to investigate the primary efficacy measure in a given trial. Conversely, if the samples are only used in relation to secondary or exploratory endpoints, which the experiment does not have sufficient power to conclude anything about, it speaks against the importance of the samples. Such samples can still contribute useful knowledge, but it requires more to justify risks to participants associated with blood sampling when these samples do not relate to a primary endpoint. Based on the above, there should, in principle, be a distinction in the assessment between blood samples related to the experiment's primary endpoint and blood samples solely taken to investigate the experiment's secondary or exploratory endpoints.

How can harm be minimized?

There are several ways to minimize harm in connection with blood sampling, which can be relevant in the individual experiment. Firstly, a limit can be set for how many times participants can have blood drawn per week, ensuring that participants do not suffer due to too frequent blood samples. Therefore, in principle, it should be ensured that blood samples are not taken from participants more than twice a week. Secondly, a maximum limit can be set for how much blood is taken over a period of two weeks to ensure participants do not experience unnecessary dizziness or other discomfort by having a large amount of blood taken from them over a short period. Thirdly, a limit can be set for how many times participants who need to have blood samples taken, which are not necessary for their own safety (i.e., research-related blood samples), will be attempted. This way, it is ensured that participants do not suffer unnecessarily from being pricked multiple times in connection with the same blood sampling. These precautions must, of course, be adjusted according to participants' age, weight, and general health condition. It also means that any fasting requirements associated with the experiment, which may call for special considerations and attention regarding blood sampling, should be taken into account.

Last updated 01-02-2024
Ikon for et reagensglas med en bloddråbe,

Content on this page