What should be done with NPH insulin in preparation for mixing?

NPH insulin, which is an intermediate-acting insulin, must be handled carefully before mixing with other types of insulin. The correct preparation method is to roll the vial gently between the palms of the hands. This gentle rolling helps to resuspend the insulin, which can settle or separate over time due to its cloudy appearance. Shaking NPH insulin vigorously can create bubbles and lead to inaccurate dosing, as it may cause the solution to foam.

By rolling the vial gently, you ensure that the insulin is uniformly mixed without causing damage to its molecular structure, maintaining its efficacy for administration. This practice also helps achieve an accurate dosage when drawing up the insulin into a syringe.

In contrast, other methods such as vigorous shaking or letting the vial sit at room temperature for a specific period are not appropriate and could compromise the insulin's effectiveness. Because the proper mixing technique is essential for accurate dosing and optimal therapeutic effect, rolling the vial is the correct preparation method for NPH insulin before mixing it with other insulins.