Proper Mixing of Insulins
The primary concept when mixing insulin products is to draw up the short
acting insulin first and add the longer-acting product to it. This avoids any
cross contamination of the short-acting insulin with the long-acting
preparation. Contamination of the long-acting with shorter acting insulin is
irrelevant. The following steps should be followed when mixing long-acting
insulins with short-acting insulin.
- Inspect vials for contamination or degradation.
- Wash hands with soap and water.
- Verify insulin source, strength, insulin syringe size as correct
- Agitate cloudy insulins (NPH in this case) by rolling between palms. New
vials may require extensive agitation to loosen bottom sediment. Regular
insulin does not require agitation. Bubbles or foam may be formed if vials
are shaken. Do not use any vial until all bubbles or foam have cleared.
- Prep vials using sterile technique (alcohol pad)
- Pull plunger of a clean syringe back to prescribed number of long-acting
- With the long-acting insulin vial resting upright on a flat surface,
aseptically, inject the air volume equal to the long-acting insulin dose
into the vial and withdraw the needle.
- Repeat the air injection process with the short-acting insulin, inverting
the vial and withdrawing the appropriate number of insulin units. Prior to
removing the syringe, inspect for bubbles. If bubbles are present, reinject
the air into the vial and withdraw the appropriate dose. Withdraw the
- Invert the long-acting insulin vial, insert the syringe, withdraw the
appropriate number of insulin units and remove the syringe from the vial.
- Draw an air bubble into the syringe, invert to mix the insulin within the
- Expel the air bubbles (recap if prep is for future use or use for