Which fingers are primarily used for adult capillary punctures?

For adult capillary punctures, the third and fourth fingers (also known as the middle and ring fingers) are primarily used due to their adequate blood supply and lower likelihood of causing discomfort. These fingers are often preferred as they are typically less sensitive than the index finger and thumb, and they provide a good surface area for the puncture.

When performing a capillary puncture on an adult, it's important to use a finger that has sufficient blood flow and is not overly callused, which can be found more on the middle and ring fingers. Additionally, using these fingers minimizes the risk of hitting a deeper nerve or structure, which could occur if the index or thumb, which are more commonly used and more sensitive, were utilized.