If you prick me, do I not bleed? No. No, I do not.

June 1, 2021 7:16 PM

I need to get a pin prick blood sample to participate in a research study. They sent me two one-time use lancets. I used both. The pricked. I felt it. I saw a hole. I didn't bleed. Like not even a little. I just tried pricking myself with a sewing needle, got past the part where it hurts and felt the flesh "give" and the needle sink in. But no blood came out. I squeezed my finger. No blood came out. I've tried three different fingers on two hands. How do I bleed for science?

I called them when the two lancets didn't work and asked them to send me more but they said they only bought the exact right number of kits and don't have any more. I said "well can I do it with a pin" and they responded with something along the lines of "Well, I can't tell you to do that, but if you want to do that, I can't stop you either.*"

The instructions said not to squeeze the finger, so I didn't when I used the lancets. But then when I tried with the needle I did squeeze and still nothing came out. As suggested by the instructions, I had rubbed my finger some before hand before the lancet attempts. I ran them under hot water for the sewing needle trial.

*Note: She first told me I could just not do it and I wouldn't participate in this part of the study, which was okie doke by her/them, but I really want the results of this pin prick blood test, which is why I want to keep trying.

posted by If only I had a penguin... to Health & Fitness (23 answers total)

have a diabetic friend? they can help w a spring loaded finger prick device that most of us have.
posted by j_curiouser at 7:25 PM on June 1, 2021 [3 favorites]

Response by poster: Two little spring-loaded things is what they sent me. Also, there's a stay at home order so I could only zoom with a diabetic friend.
posted by If only I had a penguin... at 7:27 PM on June 1, 2021

Is there a good reason not to squeeze the finger -- can you call to ask that? Every time I have had to bleed for science (well, the anemia screening before donating blood, or taking my blood sugar), my finger has been poked on the side of the pad and squeezed and massaged.

I have heard things like 'wipe off the first tiny amount of blood' but never 'do not squeeze the finger.'
posted by batter_my_heart at 7:29 PM on June 1, 2021 [3 favorites]

Try swinging your arm by your side before using the needle to get more blood to your fingertips. Put your finger on a table so you don't accidentally pull it away as you prick it. There's different kinds of lancets maybe try a different one. Some are like just a bare blade, others have a little barrel that the needle comes out of like a syringe. It hurts less to go a little bit off to the side of the pad of the finger.
posted by SandiBeech at 7:30 PM on June 1, 2021 [1 favorite]

If all else fails, maybe take a really hot shower first.
posted by aniola at 7:41 PM on June 1, 2021

Drink a big glass of water, soak your hands in very warm water for a while, then try again.
posted by Sublimity at 7:41 PM on June 1, 2021 [2 favorites]

I was recently in a COVID study that required six(!) blood spots during every test, and I have cold bloodless hands, so this was a huge problem at first. What helped was using the pad of the finger rather than the side where it hurts less, being super well-hydrated, and taking a hot bath or shower beforehand. If all else fails, a large whiskey did the trick.
posted by mostlymartha at 7:49 PM on June 1, 2021 [3 favorites]

Are you poking on the side of your finger, or the pad? The side will generally bleed more easily, in my experience.

If you go out and buy a lancet for diabetes (or borrow one), it'll generally be adjustable how deep it goes, and while the deeper ones hurt quite a bit, I've always found them effective at getting blood out, even when my hands are very cold and dehydrated.
posted by wesleyac at 8:04 PM on June 1, 2021 [2 favorites]

I mean, you could always take a quick swipe at the ball of your finger with a previously sterilized box cutter.
posted by Jane the Brown at 8:08 PM on June 1, 2021

Do NOT squeeze or apply strong repetitive pressure to the site. This may result in hemolysis or increased tissue fluid in the blood causing incorrect results.
posted by H21 at 8:15 PM on June 1, 2021 [8 favorites]

I had this problem getting enough blood for a sample at home. The telenurse said to drink a big glass of water, wait a little while, and then run my hand under water as hot as I could stand. It did help, but I still had to prick multiple fingers and massage above the prick to get enough blood.

My blood was usable even though I did massage, and even though I couldn't quite fill the container.

I also see online where they say the 3rd or 4th fingers are the best candidates. But do you have callouses? Maybe the pinky finger would have the least built up skin to pierce through, because most people use it least?

Good luck.
posted by Flock of Cynthiabirds at 8:35 PM on June 1, 2021

Drink a lot and consume a lot of electrolytes, which will help you retain water. You can get electrolyte tablets (I'm always recommending these for certain types of migraines) at health food stores or sports stores or REI. Or just eat a lot of salty, liquid soup (hello ramen packets, pho, and won ton soup), bananas, and watermelon. Or mineral water -- I love Gerolsteiner for it's high magnesium content. Try pricking an hour after that.

Oooh, if it were me, I'd also be soaking in a warm tub right beforehand - the heat will make the blood go to your extremities.
posted by amtho at 8:38 PM on June 1, 2021

I've had this problem. I was usually able to solve it by running hot water over my hands and swinging them at my sides as I walked. But it's also the case that while you're not supposed to squeeze squeeze your finger when you're taking a pinprick sample, it's okay to give it just a little nudge to get the blood moving in the right direction. I think you could probably find a video on YouTube about how to take a finger prick sample that would illustrate an okay amount of squeezing. I was very literal about this too and at my diabetes class they showed us what was an okay amount of pressure to apply.

It's possible your lancets are too narrow and the hole you're pricking is never gonna bleed. But I think it's more likely a question of getting your blood circulating into your hands and squeezing just a tiny bit.
posted by potrzebie at 8:53 PM on June 1, 2021

I've occasionally have had this problem and going on the side, as batter_my_heart mentioned, sometimes works better. Perhaps you're either not going deep enough or the hole's not wide enough? In either case, targeting thinner skin should help, either by choosing a different finger (like pinky, as Flock of Cynthiabirds suggested) or a different part of the finger (like side).
posted by Mr.Know-it-some at 8:54 PM on June 1, 2021

Any reason it has to be fingertip? Can you not prick your wrist or lower on a finger or your lip or something? H21 seemed clued in.
posted by Iteki at 9:01 PM on June 1, 2021

I have this too! The combo that worked for me was drink lots of water, have a long hot bath, vigorous rubbing of hand (think trying to start a fire with the friction!) and finally, using my ‘best’ finger at the side. I didn’t squeeze but did apply a tiny bit of gentle pressure to get a bead from the pin prick. My best finger was my pinky along the side. Your best finger may vary!
posted by t0astie at 12:18 AM on June 2, 2021

Those spring-loaded one-time lancets are such a boondoggle. They are designed for two, largely mythical, problems 1) leaving contaminated sharps 2) folks not performing a goldiloxian [not too deep, but don't wimp it] stab. The previous solution was sterile foil-wrapped steel lancets with a -_V- end profile which worked fine. The most bleedy part of the finger is the top just above the cuticle: thin skin which heals quick.
posted by BobTheScientist at 12:20 AM on June 2, 2021 [1 favorite]

IMO, you have to leave it in for a few seconds for it to work. I have the same issue with our diabetic dog. If you immediately pull it out, she won't bleed.
posted by The_Vegetables at 7:29 AM on June 2, 2021

I've used lancets before, the spring loaded kind for blood sugar testing. I think I had to set it to 4 or higher, and press it pretty hard into the tip of my finger, and trigger to get it to draw blood. I don't think I'm thick-skinned at all. :)
posted by kschang at 11:28 AM on June 2, 2021

So I’m going to guess this is the Covid Antibodies test for the Ontario Health Study. The lancets they send are very very stiff to use (are you SURE they fired? Sounds like it but they are much stiffer than standard finger poke lancets) and are actually a teeny spring loaded blade. Which is...very ouch. Do you have a friend who is a nurse or paramedic who could ‘obtain’ a spare single use lancet or two? They are common in basically any healthcare setting. Your local pharmacist may have them as well. There are also ‘heel poke’ lancets which are used to get large samples on babies. Using one of these would make a bigger ‘ouch’ on your finger, but should give you a MORE than adequate sample. Lots of good advice above about warm hands, well hydrated, and let your hand dangle before trying to it is full of blood. Thank you for participating in science!!
posted by Northbysomewhatcrazy at 6:35 PM on June 2, 2021 [1 favorite]

Also try relaxing arm/lowering your hand while you squeeze slightly.
posted by 10ch at 9:39 PM on June 2, 2021

I am ALSO participating in a research study that requires blood spot samples - possibly the same one, but also possible not. The study that I am participating in had really good instructions for getting a good blood flow:

- soak the finger in warm water for several minutes
- rub down the warmed finger firmly to get blood into the tip

I had some very nice blood flow for my five spots - and only had to use 1 lancet.

PS: if you need another lancet, we have the extra one kicking around, but you have to pick up.
posted by jb at 1:59 PM on June 7, 2021

I had a nice little instruction booklet, but not sure if I kept it. They are doing follow-ups, so I'll photograph if they send another.
posted by jb at 2:02 PM on June 7, 2021