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

When using a blood pressure cuff to locate a vein for blood sampling, what level should it be inflated to?

1. 20-30 mmHg

2. 40-50 mmHg

3. 60-80 mmHg

4. 90-100 mmHg

The correct answer is: 60-80 mmHg

Inflating the blood pressure cuff to a level of 60-80 mmHg is considered optimal for locating a vein for blood sampling. This pressure range effectively occludes venous return while still allowing arterial blood flow to maintain pulsation in the area being examined. By inflating the cuff within this range, the blood pooling in the veins makes them more prominent and easier to visualize and palpate, facilitating the process of venipuncture. If the cuff is inflated too low, the veins may not become sufficiently distended, making them difficult to locate. Conversely, inflating the cuff too high may restrict arterial flow significantly, potentially causing difficulty in identifying the veins due to reduced pulsation and blood supply to the area. In summary, the 60-80 mmHg inflation range allows healthcare professionals to balance the need for venous distension while maintaining enough arterial flow to easily identify a suitable vein for blood sampling.