Before venipuncture, what instruction helps ensure accurate results when a patient would otherwise squeeze their fist?

Before venipuncture, what instruction helps ensure accurate results when a patient would otherwise squeeze their fist?

• A. Instruct patient to relax the hand and avoid squeezing
• B. Have patient clench the fist
• C. Apply tourniquet tightly for long
• D. Instruct patient to tilt head

Answer: (A)

Relaxing the hand and avoiding squeezing prevents altering the blood that’s drawn. When a patient pumps the fist or clenches, muscle activity and venous pressure push fluid out of the tissue into the blood and slow venous return, causing hemoconcentration. This changes concentrations of several analytes and can yield falsely elevated values (for example, potassium) and other inaccuracies. By instructing the patient to relax the hand, you keep the sample closer to the true circulating levels, improving accuracy. Other options don’t support accuracy in the same way: clenching the fist worsens hemoconcentration; keeping the tourniquet on too long can also cause changes in the sample, and tilting the head doesn’t affect venipuncture accuracy.

Relaxing the hand and avoiding squeezing prevents altering the blood that’s drawn. When a patient pumps the fist or clenches, muscle activity and venous pressure push fluid out of the tissue into the blood and slow venous return, causing hemoconcentration. This changes concentrations of several analytes and can yield falsely elevated values (for example, potassium) and other inaccuracies. By instructing the patient to relax the hand, you keep the sample closer to the true circulating levels, improving accuracy.

Other options don’t support accuracy in the same way: clenching the fist worsens hemoconcentration; keeping the tourniquet on too long can also cause changes in the sample, and tilting the head doesn’t affect venipuncture accuracy.