Percentage concentration (March 2026 NMC update)
| Site: | Computer Based Test (CBT) Provided by ONT Global Academy |
| Course: | Part A Numeracy |
| Book: | Percentage concentration (March 2026 NMC update) |
| Printed by: | Guest user |
| Date: | Sunday, 6 September 2026, 2:20 PM |
1. Percentage concentration
With NMC recent CBT exam update (March 2026) percentage concentration question might be asked in your NMC CBT exam.
Let us have a look how the percentage % (w/v) calculation works.
Drug concentration may also be measured as percentage % (w/v). Percentage means the number of grams of drug dissolved in 100ml solution, i.e. g per 100ml. This is irrespective of the size of the vial or bottle of fluid: e.g. Dextrose 5% infusions means that there are 5 grams of Dextrose dissolved in each 100ml of fluid, and this will remain the same if we have a 500ml infusion bag or a 1 litre infusion bag.
1 litre of 10% Dextrose means 10 gram Glucose in every 100 mL
Example-1,
Dextrose 50% injection in a 25ml vial. Patient prescribed 20g. How many mL?
50 % = 50 g in 100 mL
20 ÷ 50 x 100
Answer: 40 mL
Example-2,
Calcium Chloride 10% injection in a 10ml ampoule. How much is needed for a patient prescribed 2g?
10 % = 10 g in 100 mL
Apply formula,
Dose required ÷ Dose available x volume
2 ÷ 10 x 100 = 20 mL (i. e. 2 ampoules)
One in ….. concentration
This final type of concentration method is used only occasionally, e.g. tuberculin, adrenaline. 1 is stated as 1 in 100, 1 in 10,000, etc, and means grams in ml.
Thus: 1 in 100 means 1g in 100ml
1 in 1000 means 1g in 1000ml
1 in 10,000 means 1g in 10,000ml
Therefore, it can be seen that 1 in 1000 is a WEAKER strength that 1 in 100, and 1 in 10,000 is WEAKER than 1 in 1000.
Example: We want to give 1mg tuberculin using 1 in 1000 strength solution.
1 in 1000 strength solution means 1 g in 1000 Apply formula, Dose required ÷ Dose available x Volume its in 1mg ÷ 1000mg x 1000 = 1 mL Example-1, Give 1mg of epinephrine using the 1 in
10,000 solution. 1 in 10,000 means 1g in 10,000 mL, i.e. 1000 mg in 10,000 mL Apply formula, Dose required ÷ Dose available x Volume its in 1mg ÷ 1000mg x 10,000 = 10 mL Example-2, Give 5mg tuberculin using 1 in 100 solution 1 in 100 means 1g in 100 ml, in mg, 1000 mg in 100 mL Apply formula, Dose required ÷ Dose available x Volume its in 5mg ÷ 1000mg x 100