NMC OSCE fluid balance questions

Where fluid balance fits in the NMC OSCE

Fluid balance is one of the adult skills topics in the NMC's September 2026 timings PDF (timings PDF). It is listed at 14 minutes, with an assessor present (NMC booklet). The chart is an input and output record with running totals over 24 hours. See the stations list.

A worked example with invented numbers

These numbers are made up to show the principle. They are not from any real station.

Total input is 250 + 200 + 500 + 150 + 500 = 1,600 ml. Total output is 400 + 300 + 350 + 100 = 1,150 ml. The balance is 1,600 minus 1,150, which is plus 450 ml. A positive balance means more went in than came out.

What to do with the answer

1. Check the arithmetic twice, and write the units in full.
2. Say whether the balance is positive or negative, and by how much.
3. Link it to the patient: look at observations, breathing, swelling and what the patient says.
4. Report to the nurse in charge or doctor if it worries you, in line with local policy.
5. Document clearly: signed, dated and timed, in black ink.

The chart does not say what is safe for any one patient. That needs a clinician's judgement, so say who you would tell.

Common slips

Forgetting an IV bag, missing vomit or stool from output, mixing up litres and millilitres, and stopping once the sum is done. Practise a few made-up charts, then run a timed skill in the NMC OSCE practice test. The habits assessors look for, such as a clear explanation and legible notes, are in the marking criteria guide.

Common questions

What are NMC OSCE fluid balance questions?

They ask you to total fluid input and output on a chart, find the balance and explain what it means for the patient.

How do you calculate a fluid balance?

Add everything that went in, add everything that came out, and subtract output from input. A positive result means more went in.