Measuring Intake and Output
Measure, convert and record what a patient takes in and puts out, and know which totals to report.
Table of contents
Intake and output, written I&O, is a record of all the fluid that goes into a person's body and all the fluid that comes out. Nurses and providers use it to check hydration, kidney function and fluid balance, and they make treatment decisions with it. A careless number can mean a wrong decision, so measure exactly.
What You Will Be Able to Do
- List what counts as intake and output.
- Measure output correctly in a graduated container.
- Convert household amounts to milliliters.
- Add up a shift's totals.
- Report results that need attention.
What Counts
| Intake | Output |
|---|---|
| Water, juice, coffee, tea, milk | Urine |
| Soup and broth | Vomit (emesis) |
| Gelatin, ice cream, sherbet | Liquid stool |
| Ice chips | Wound drainage |
| Tube feedings | Ostomy output |
| IV fluids (usually recorded by the nurse) | Blood loss and suction (usually recorded by the nurse) |
A simple rule for intake is that anything liquid at room temperature counts. Gelatin and ice cream count because they melt. Pureed food does not count.
Measuring Intake
Measure what the person actually drank, not what you served.
- Write down the amount you serve.
- Measure what is left when they finish.
- Subtract.
Most units record in milliliters (mL). You may see cubic centimeters (cc), which equal the same amount.
| Household measure | Metric |
|---|---|
| 1 ounce | 30 mL |
| 1 cup or 8 ounces | 240 mL |
| Small carton of milk | About 240 mL |
| Juice box | About 120 to 200 mL (check the label) |
| Bowl of soup | About 180 mL |
| Ice chips | Count as about half their volume |
Facilities often list the size of their own cups and bowls. Use your facility's list instead of a guess.
Measuring Output
- Wear gloves.
- Ask the person to use a urinal, bedpan or a hat, a plastic container that sits in the toilet. Ask them not to put toilet paper in it.
- Pour the output into a graduated container.
- Set the container on a flat surface and read it at eye level.
- Empty it, rinse it and clean your hands.
- Record the amount right away.
For a urinary catheter, drain the bag into a graduated container and measure. Do not rely on the marks on the bag. They are only estimates.
For an incontinent person or a baby, the nurse may ask you to weigh the brief or diaper. Weigh it wet, subtract the weight of a dry one, and count 1 gram as 1 mL. Otherwise note how many times it was soiled and whether it was small, medium or large.
Worked Example
Mrs. Ortiz is on I&O for an 8-hour shift.
| Intake | mL |
|---|---|
| Breakfast: 6 ounces of juice | 180 |
| Breakfast: 1 cup of coffee | 240 |
| Mid-morning: 120 mL of water, half finished | 60 |
| Lunch: 1 bowl of soup | 180 |
| Lunch: 4 ounces of gelatin | 120 |
| Afternoon: 1 cup of ice chips | 120 |
| Total intake | 900 |
Output during the same shift was 250 mL at 9:30, 200 mL at 12:00 and 150 mL at 2:30, for a total of 600 mL.
Her intake is 900 mL and her output is 600 mL. You record the numbers. The nurse decides what they mean.
What to Report
- Urine output under 30 mL an hour for an adult, or the amount on the care plan. That is about 240 mL in 8 hours.
- A sudden drop in output, or no urine at all.
- Urine that is dark, bloody, cloudy or strong-smelling.
- Output that is a lot higher than intake, or a lot lower.
- Vomiting or diarrhea.
- Refusing to drink, or drinking much less than usual.
- A patient on a fluid limit who drinks more than the limit.
Fluid Orders to Know
- Force fluids means encourage more drinking.
- Fluid restriction means the person has a daily limit. Stick to it, and report if they ask for more.
- NPO means nothing by mouth, not even water or ice, unless the nurse says otherwise.
Do not decide on your own to give or hold fluids. Check the care plan or ask the nurse.
Common Mistakes
| Mistake | What it costs |
|---|---|
| Recording what you served, not what was drunk | The total is too high |
| Forgetting soup, gelatin or ice chips | The total is too low |
| Reading a container held in your hand | Wrong measurement |
| Letting a patient flush the toilet before you measure | Missing output |
| Waiting until the end of the shift to record | Lost or guessed numbers |
Check Your Understanding
1. A patient drinks 180 mL of a 240 mL carton of milk and finishes 4 ounces of gelatin. What is the total intake?
180 mL plus 120 mL equals 300 mL.
2. You empty a urinary drainage bag and the total for 8 hours is 200 mL. What do you do?
Measure it in a graduated container, record it and report it to the nurse. It is under 30 mL an hour.
3. A person has a cup of ice chips. How much do you record?
About half the volume, so about 120 mL for a 240 mL cup.
4. Is mashed potato counted as intake?
No. Count only what is liquid at room temperature.
Key Takeaways
- Count everything liquid at room temperature.
- Record what was actually taken, in mL.
- 1 ounce is 30 mL, and 1 cup is 240 mL.
- Measure output in a graduated container at eye level.
- Report adult urine output under 30 mL an hour, or any big change.