Table 2 Feasibility

Description of the self-sampling process

“Well, first you should tear open the bag, which contains the device. Then there is also a heat pack, which you have to apply to warm the skin. (…) [A]nd then you need the small bag for disinfection. Before you hold the device or press it, you first have to disinfect the arm and then you activate the device. There is a button and you press it and that is practically the needle where the blood goes in. It's a small container that you have to unscrew beforehand and then you press it so that the blood enters. You have five minutes, a maximum of five minutes, so that the amount of blood- There is a label on it, that's how much blood should be in the small container. Then you can remove it [the collection tube] if you think you have enough blood and then you close it and label it. (…) Then it is packed in a bag and then [put] in a small cardboard box. So you can simply give it to the post office. That would be it.” (Patient 6, Sjögren's syndrome, Tasso + : 05:24)

Positive experiences

“I was totally surprised how easy it was and how painless it was. I think that's great.” (Patient 3: Systemic lupus erythematosus, 05:48)

“Everything worked. I did it all as it was written in the instruction manual. I didn't need any help. It may have taken a little longer because the first time I took a spot in my upper arm where maybe not as many veins go through. I first thought maybe nothing was coming out, but actually blood was still coming out to the extent that it should be and was sufficient for the exam.” (Patient 7, Rheumatoid arthritis, Tasso + : 03:49)

“Okay. Yes, so first he [the study nurse] showed me the video—he had a video and then on paper, on a poster actually—how you have to do it. That was absolutely understandable. Then I did it right away. (…) I took the blood myself. I practically did the procedure, everything that had to be done. This worked very well.” (Patient 12, Systemic lupus erythematosus, Tasso + : 03:00)

Negative experiences

“For whatever reason… I do not understand it. It started bleeding again after an hour. I do have an autoimmune disease; I have delayed wound healing. But there was definitely a crust for a week afterwards. Didn't hurt though, the blood collection. It is not painful. It's painless.” (Patient 4, Sjögren's syndrome, Tasso + : 01:32)

“I don't know whether it stays or goes, but I still have these little red dots on my arm, (…) I don't know if these marks will stay or that will go away with time.” (Patient 9, Systemic lupus erythematosus, TAP II: 06:42)

“So as I said, with the bruise there, this red squiggle, when you have several on your arm, that really doesn't look nice.” (Patient 1, Rheumatoid arthritis, TAP II: 04:40)

“However, I had talked to the study nurse, that the device is not so pleasant for environmental reasons, because it can't be used more than once. And this garbage, which then accumulates every time with such a sampling, well, the manufacturer should change something, so that at least the same person can use the device more than once.” (Patient 1, Rheumatoid arthritis, TAP II: 01:02)

“The only thing I had problems with was my Raynaud's syndrome, I have problems with my finger joints to apply the force. So the button was quite difficult for me to push through and that worked, but when I took it off, it [blood] ran out quite difficult… into the collecting tube.” (Patient 2, Systemic sclerosis, TAP II: 07:23)

"What bothered me a bit was that after removing the device from the arm, there was a relatively large amount of blood on the arm. What further bothered me was that it takes a certain amount of care or skill to then remove this tube from the device and close it correctly.” Patient 8, Granulomatosis with polyangiitis TAP II: 07:20)

“I have to take it to the post office. And the post office is no longer emptied three times a day, but once in the evening at 5 p.m. or 6 p.m., I don't know exactly. And then it goes out the next day. By the time it reaches the institute that evaluates the blood, time has already passed. If it is unfavorable also still in the summertime with high temperatures….” (Patient 10, Sjögren's syndrome, TAP II: 03:53)