(3) When measuring U-100 insulin (100 units per ml) in a 1 ml tuberculin
syringe, the number of units ordered will always equal an equivalent number of
hundredths of a milliliter. Therefore, to measure 16 units of U-100 insulin, measure to
the 0.16 ml mark on the tuberculin syringe. Be sure to use the cc scale on the syringe.
Figure 2-5. Measuring insulin in a tuberculin syringe.
(4) Calculations for insulin dosages are carried out in the same manner as
for other parenteral medications. However, as with heparin, all insulin calculations
should be rounded to the hundredth place.
EXAMPLE: The order is to give 20 units of Regular Insulin. You are
using U-100 insulin and a tuberculin syringe. What is the
100 units = 20 units
100X = 20
X = 0.2 ml
PRACTICE: The order is to give 30 units of NPH insulin SC. Available
is a 10 ml vial labeled U-100 NPH insulin. Calculate the
amount of insulin to give.
100 units = 30 units
100X = 30
X = 0.3 ml
e. Calculation of Medication Based on Body Weight. Medication doses are
often based on the patient's body weight, especially with infants and children. Although
this is primarily a professional responsibility, you may use the manufacturer's
recommendations to determine if a prescribed dose is a reasonable dose to administer.