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Reconstitute to Final Bag

Calculate final bag concentration after reconstituting a vial and adding part of the solution to an infusion bag.

CalculatorHow it worksFormulaWorked examplesWhen usedFAQsReferences

Calculator

Use the **final vial volume** after reconstitution (label/monograph).

Use the volume your policy uses for the final concentration check.

Educational use only. Always verify against product information and local policy.

How it works

This is a two-stage process: first you reconstitute the vial to obtain a vial concentration (mg/mL). Then you withdraw a volume from the vial and add it to an infusion bag.

The calculator performs three steps: (1) vial concentration, (2) mg withdrawn/added, (3) final bag concentration (mg/mL).

Formula

C(vial) = mg in vial ÷ final vial volume (mL)
mg added = C(vial) × mL withdrawn
C(final) = mg added ÷ bag volume (mL)

Worked examples

Example 1: 1000 mg vial, reconstitute to 10 mL, withdraw 5 mL, add to 250 mL bag

C(vial) = 1000 ÷ 10 = 100 mg/mL
mg added = 100 × 5 = 500 mg
C(final) = 500 ÷ 250 = 2 mg/mL
Answer: 2 mg/mL

Example 2: 500 mg vial, reconstitute to 5 mL, withdraw 2 mL, add to 100 mL bag

C(vial) = 500 ÷ 5 = 100 mg/mL
mg added = 100 × 2 = 200 mg
C(final) = 200 ÷ 100 = 2 mg/mL
Answer: 2 mg/mL

Example 3: 750 mg vial, reconstitute to 15 mL, withdraw 6 mL, add to 500 mL bag

C(vial) = 750 ÷ 15 = 50 mg/mL
mg added = 50 × 6 = 300 mg
C(final) = 300 ÷ 500 = 0.6 mg/mL
Answer: 0.6 mg/mL

When this calculator is used

  • •Reconstituting powder vials (e.g., antibiotics, chemo) and adding to infusion bags
  • •Two-stage dilution checks prior to administration
  • •Standardizing final infusion concentrations for protocols
  • •Education/training and double-checking calculations

Clinical safety note: Use the diluent and volumes specified on product information and follow local policy. Always verify final concentration before administration.

Related calculators

C1V1 = C2V2 Basic

Serial 2-Step Dilution

C1 to C2 Final Volume

Frequently asked questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & sources

Institute for Safe Medication Practices (ISMP)

Medication safety guidance and error prevention

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ACSQHC Medication Safety Standard (NSQHS)

Australian medication safety standard

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SI Prefixes (milli-, micro-, etc.)

BIPM metric prefixes reference

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