Any advice about lab draws or procedures that require a degree of cooperation from the patient with dementia?

Make sure the person getting stuck is well hydrated prior to the lab draw.
Ask if the person drawing the lab can use a butterfly needle (small 21ga needle) instead of the vacutainer huge needle used generally. Dangle to hand lower and apply a light tourniquet to help engorge the veins via gravity.
Start low on the arm just in case the vein blows. Then they can try above that site.
It can be very difficult to draw labs on an elderly person due to small veins & not cooperating.
I did this a lot in homecare nursing. I know it’s hard but try to get an experienced phlebotomist.
Someone should be there to assist in the procedure to sooth the patient and in some cases help hold the arm in place.

You may want to consider whether the test or procedure is actually needed.

When my grandmother's red cell count was low, the treatment was a transfusion; however, the doctor still wanted to redo a painful test to "find" the bleeding from her colon he was sure was the cause of the low red cell count. I asked how the test results would impact her treatment and what he would want to do if the test came back negative again. Treatment would not change and he would accept that Grandma was probably not making enough blood cells anymore because of her advanced osteoporosis. The femur makes the most blood and a hip replacement years prior had reduced the amount of femur available. We refused the repeat test because it had no impact on Grandma's care, just might have allowed the doctor to check off a box. For the rest of her life, the blood cell count was monitored and she received a transfusion when it fell too low. Her PCP told us she was grateful we refused the test the specialist wanted.

Just to restate what was mentioned along the way...determine how necessary the lab work is. Is it just to cover the bases? Is the person otherwise healthy? Someone can be absolutely fine, then get symptoms and REALLY need lab work done which would show something. Thanks to advice here and a change in my thinking on it, I passed the last 6 month re-check visit for my folks. Even the practitioner was sort of shoulder shrugging as to when they should return (thank goodness they are in good health at 97 and 102). You get to the point sometimes where it's sort of live and let live. The stress of it all (for the caregiver as well) may not be worth it. Of course my philosophy got me in trouble last week when dad complained (like I could do something) again about how much mom with dementia eats snacks and sweets and drinks "a lot" of pop. I said it hadn't killed her yet. LOL...not the right thing to say to deaf dad who read my comment via an app on his iphone screen. He thought I was wishing her dead. He is clueless and her labs have been fine as long as this has been going on. Perhaps the bad is counteracted by the olives and fruit she eats...but he's the one who brings the snacks into the house and of course you all know how hard it can be to get someone to drink/keep fluids up. So although the pop isn't the best choice, if she's drinking it at 97, I say drink on. If we can learn not to get so concerned about some of this stuff, it will reduce our own stress as well as that of those we care for.

Good point TNtechie. My mom's doctor thought she should be getting routine blood tests a couple of times a year and once she was housebound taking her out or finding a mobile clinic became a real ordeal, not to mention unpleasant for mom. Sometimes we need to learn to just say no.

Although a nurse comes to the home to do an occasional blood draw, my mother will no longer cooperate. She refuses. Her health is okay, no emergencies, so they are following her choice and stopping them as a routine.

Mom doesn't have dementia, but she's terrified of needles, and her flesh is quite sensitive, so the tourniquet really hurts her. So: I boost fluids for a couple of days before lab work to help the flow, and I hit on the idea of giving her a stuffed kitty (that meows and purrs when rubbed) as a comfort and distraction. She also holds and talks to the kitty when she's getting her B12 injection.

Funny story: Before I got the stuffed kitty idea, when Mom was still able to travel to the doc's office for her tests, I decided to sing to her while she was getting blood drawn. This was a spur-of-the-moment idea, and the only song I could think of was "Show Me the Way to Go Home." Mom joined me in the chorus and we got a little rowdy, but they got the blood they needed, and the folks in the waiting room got some entertainment.

They’ve put my husband’s arm on a board as one person holds it steady and the other draws the blood. Key is someone who gets a good stick the first time.

Am so glad this question was raised, as my mom of 96 with dementia just had this experience. I thought this fear of needles was hers alone. The lab technician had to go the route that she takes with children she said. She pricked the tip of her finger and squeezed enough blood out into a tube. My mother was beside herself with fright. Needless to say, the ride home from the doctor was interesting.

You have some good suggestions about hydration prior to the draws. You might also ask friends/family who they take very young children to. Those folks have some very unique ways of sidetracking little kids in order to give shots and draw blood.

Do you know her medical wishes? My 95 year old mother's end of life wishes were 'no heroic measures.' She has severe dementia and reacts very badly to hospital stays and doctor visits. She tears off her oxygen, refuses shots, bites the nurses when they try to put something on her, etc. The trips to the eye doctor were useless, she didn't understand any of the instructions. She has no understanding of why she needs to go to the dentist. In consultation with her doctor, we decided to put her in hospice-type care where we only make her comfortable. We have cancelled all doctor and dental visits except for the 3-month doctor visit where just the basics are done. We changed her medical directives to say "no hospitalization" unless it's an acute emergency like bleeding. All this is meant to say that if she refuses treatments and is miserable when you try to have things done, perhaps it's better to stop trying and let nature take its course.