A collection tube, with an internal vacuum, used to draw blood samples(noun)
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Use "vacutainer" in a sentence
"Packaging is important - buy a sturdy plastic container that's big enough to accommodate the food you want your child to take to school without getting squashed, and consider buying a small non-breakable vacuum flask or vacutainer for keeping cold foods and drinks cold, and hot foods and drinks hot"
"Baked potato with a filling (keep warm in vacutainer)"
"Hot chocolate or cocoa made with skim milk (keep warm in vacutainer during winter)"