Baby vs. Butterfly Needle

Question

How do they differ? They're mentioned here. I prefer a smaller needle to lessen pain for blood tests.

Answer 1

There's no such thing as a baby needle. That's just a term somebody made up to describe a small needle. The diameter of needles is measured in Birmingham gauge. The smallest needles commonly made are 34 gauge, which has an outside diameter of .1842 mm. Compare that to 18 gauge, the size typically used to draw blood samples. A 34 gauge needle is almost 7 times smaller than an 18 gauge, which is 1.270 mm in diameter.

A butterfly needle is another name for a winged infusion set, or a "scalp vein" needle. It's called that because it has tabs attached to it that look somewhat like butterfly wings. It has nothing to do with the size, although butterfly needles usually are a smaller gauge.