American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

At what angle should the needle used for venipuncture be inserted into the skin?

1. 30 degrees

2. 15 degrees

3. 45 degrees

4. 90 degrees

The correct answer is: 15 degrees

For venipuncture, the ideal angle for needle insertion is typically around 15 degrees to 30 degrees relative to the skin surface. In this context, inserting the needle at 15 degrees allows for a more controlled access to the vein while minimizing the risk of damaging surrounding tissues. This angle strikes a balance between ensuring that the needle enters the vein without going too shallow, which could miss the vein, or too deep, which could lead to complications. Using a lesser angle like 15 degrees promotes better visualization and accessibility of the vein, especially for healthcare professionals who are performing the procedure, as it aligns the needle trajectory more closely with the anticipated path of the vein beneath the skin. This is particularly important in areas where veins are more superficial. Angles such as 30 degrees or 45 degrees may still be acceptable in various scenarios and may be used depending on the clinician's preference or the patient's anatomy, but a 15-degree angle is a common standard, especially for novice practitioners or in situations where there is a need for precision. Inserting the needle at 90 degrees is generally inappropriate for venipuncture as this would likely cause more trauma to the vein and surrounding tissues, making it less effective.