Calculating Intake and Output on the NCLEX-RN

Calculating Intake Output

When caring for patients, you will frequently be required to calculate strict intake and output data, and therefore you should be prepared to complete this on the NCLEX-RN exam. Keep practicing questions to help you master the skills that are on the NCLEX-RN exam.

Calculate Intake

Calculating a patient’s daily intake will require you to record all fluids that go into the patient. This includes oral intake, tube feedings, intravenous fluids, medications, total parenteral nutrition, lipids, blood products, dialysis fluids and flushes. Most institutions require the nurse documents the input every one to two hours. Some patients that are fluid sensitive and critically ill will require strict measurements, which means every milliliter of fluid needs to be accounted for.

With the use of intravenous pumps, measuring the total intake is easily recorded from the pump. If a pump is not used, then the nurse should record the total volume of the bag or if only part of the bag is infused, estimate as best as possible. Oral intake can be a little tricky because you are not always in the room when the patient drinks. A few suggestions to help with this include having the patient save all empty drink containers and also provide the patient or parent with paper and a pen to record what they eat or drink throughout the day.

Estimate the patients 8 hour (3pm-11pm) intake:

IVF @ 25cc/hr continuous

TPN @ 50cc/hr continuous

Lipids at 10cc/hr for 12 hours (8pm-8am)

NGT feeds @ 25 cc/hr continuous

2 units of blood – 250ml/unit – first unit at 10am/ second unit at 4pm

IV Vancomycin – 250ml every 12 hours at 8am/8pm

Calculate Output

Calculating a patient’s daily output will require you to record all fluids that are excreted or withdrawn from the patient. This includes urine, liquid stools, drainage from drains or chest tubes, in critical areas blood. Basically, you will check all urine bags, drains and collection canisters every one to two hours. If a patient uses diapers or voids on the protective pad, you can weigh a dry one and then weigh the soiled one subtract the standard weight to calculate the output. Remember that patients also have insensible loses that can not be measured, fluids which are lost through the skin, such as sweat when febrile or sweating excessively.

Estimate the patient’s 8 hour (3-11pm) output

4pm – 100ml urine

4pm – suction canister 50ml

4pm – chest tube 15ml

6pm – Urine 150ml

6pm -chest tube 10ml

8pm – urine 110ml

8pm – chest tube 5ml

8pm – suction 50ml

11pm – urine 60ml

Calculate Intake/Output Ratio

This requires you to determine the difference between the amount that goes in and the amount that is out. If there is a large discrepancy, the medical team may need to make adjustments. Often times when there is a major difference, you should first check your calculations, then assess your patient which often times includes getting a current weight so you will have all of the information required by the medical team. If you have a positive number, the body has retained fluids, where as a negative number demonstrates that more fluids have been lost than taken in putting the patient at risk for dehydration.

What is the difference between the patient’s intake and output above?

Would this concern you?

What Interventions might be required?


Total Intake = 1330

Total Output = 550

Difference +780

Concern for fluid overload – Patient may require a diuretic