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What is the difference between U-40 and U-100 syringes?

A U-100 syringe has 100 unit marks per mL (1 unit = 0.01 mL). A U-40 has 40 per mL (1 unit = 0.025 mL). Reading a U-100 number off a U-40 barrel gives 2.5× the intended volume.

Math only, not medical advice. This page converts numbers; it does not recommend any compound or amount.

Draw to
10 units
= 0.1 mL · concentration 2.5 mg/mL (2500 mcg/mL) · 20 draws per vial
Concentration = 5 mg ÷ 2 mL = 2.5 mg/mL
Volume = 250 mcg ÷ 2500 mcg/mL = 0.1 mL
Units = 0.1 mL × 100 (U-100) = 10 units
0102030405060708090100

Math only, not medical advice. Verify every number yourself.

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