Inversion should be performed in which manner to avoid damaging the sample?

• A. Gently inverting.
• B. Vigorously shaking.
• C. Rapid twisting.
• D. Rolling the tube on a bench.

Answer: (A)

Gently inverting the tube is preferred to mix the sample and any additive without causing damage. This method distributes additives evenly while minimizing shear forces that can harm cells or proteins. Vigorous shaking or rapid twisting can cause hemolysis or rupture of delicate components, and rolling the tube on a bench may not mix thoroughly and risks spills. So, invert gently end over end several times (usually five to ten) with the cap secured.