Injection Volume and Concentration
Calculate injection volume from the prescribed dose and supplied concentration.
How to prepare for the NMC Midwifery CBT
Combine unit-safe calculation with newly qualified midwife judgement grounded in the Code, informed choice, continuity, physiology, timely escalation and collaborative care.
Core concepts
Concept 1
Concentration and presentation volume must remain paired.
Exam cue: Align dose units before dividing.
Concept 2
Route and formulation determine whether the calculated volume is plausible.
Exam cue: Check the route after calculating.
Risk pitfalls and guardrails
Treating total vial content as per-mL concentration.
Guardrail: Do not choose a familiar task if it ignores deterioration, consent, medicines risk, scope, communication or follow-up.
Assuming one ampoule always equals one dose.
Guardrail: Do not choose a familiar task if it ignores deterioration, consent, medicines risk, scope, communication or follow-up.
Memory anchors
What is the injection-volume formula?
Required dose ÷ stock dose × stock volume.
Why does route matter?
Routes have different practical and safety limits.
What must be aligned first?
Prescription and stock dose units.
Does one ampoule always mean one dose?
No; use the labelled content and concentration.
What follows an unexpected volume?
Recheck units, concentration and prescription.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
An ampoule contains 300 mg in 2 mL. A dose of 600 mg is prescribed. What volume is required?
An injection contains 50 mg in 2 mL. The prescription is for 25 mg. What volume is required?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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