Measuring Intake & Output, Height & Weight
Key Takeaways
- One ounce equals 30 mL, so an 8 oz glass is 240 mL and a 4 oz carton is 120 mL — memorize the conversion, not the individual containers.
- Intake includes every liquid plus foods that are liquid at room temperature: gelatin, ice cream, sherbet, popsicles, ice chips at half their volume, and soup broth.
- Output includes urine, emesis, liquid stool, wound drainage, and drainage from tubes; on the NNAAP skill urine is measured at eye level on a flat surface and recorded within plus or minus 25 mL.
- Weigh at the same time of day, on the same scale, in similar clothing, after voiding — and always zero the scale before the resident steps on.
- A gain or loss of 2 to 3 pounds in a day, or 5 pounds in a week, is reported immediately; it usually reflects fluid, not fat.
Measuring Intake & Output, Height & Weight
"Measure intake and output" and "report and record weight and height" are both written into Rhode Island's list of nursing assistant duties (216-RICR-40-05-22.12.1(A)(2)). They are also the numbers that most often reveal a developing problem before anyone feels sick: a resident in early heart failure gains fluid weight days before becoming short of breath, and a dehydrating resident's output falls before confusion sets in.
Fluid Conversions
Learn the single conversion and derive the rest:
1 ounce (oz) = 30 mL = 30 cc
| Common container | Ounces | mL / cc |
|---|---|---|
| Small juice or milk carton | 4 oz | 120 mL |
| Bowl of soup | 5 oz | 150 mL |
| Cup of coffee or tea | 6 oz | 180 mL |
| Glass of water | 8 oz | 240 mL |
| Can of soda | 12 oz | 360 mL |
| Water pitcher (typical) | 32 oz | 960 mL |
Exam items usually give you two or three containers and ask for a total. A resident drinks a 6 oz coffee, an 8 oz water, and a 4 oz gelatin cup: 180 + 240 + 120 = 540 mL.
What Counts as Intake
Intake is everything liquid at room temperature, not just drinks:
- Water, coffee, tea, juice, milk, soda, nutritional supplements
- Soup broth
- Gelatin, ice cream, sherbet, popsicles, custard
- Ice chips count as half their volume — a 200 mL cup of ice chips records as 100 mL
- Intravenous fluids and tube feedings (recorded by the nurse, but you report what you observe)
Solid foods, even watery ones like watermelon, are not counted as fluid intake.
Recording meal intake
Food intake is charted as a percentage of the meal consumed, usually in 25% increments:
0% -> ate nothing (refused, or NPO)
25% -> ate about one quarter
50% -> ate about half
75% -> ate about three quarters
100% -> ate the entire meal
Report any meal below 50% to the licensed nurse. Two or three consecutive poor meals is a nutrition problem that needs a dietitian or a swallowing evaluation, not a note at the end of the week.
What Counts as Output
- Urine — the largest and most frequently measured component
- Emesis (vomit) — measure it; do not discard it before the nurse sees it
- Liquid stool / diarrhea — estimated per facility policy
- Wound drainage and drainage from tubes and drains
- Excessive perspiration and wound weeping are described, not measured, but should be reported
Normal urinary output
| Measure | Normal | Report |
|---|---|---|
| Per 24 hours | About 1,200–1,500 mL | Under 500 mL/24 h, or a sudden drop |
| Per hour | At least 30 mL/hour | Less than 30 mL/hour |
| Absence | — | No urine at all (anuria) |
Other terms you must recognize: oliguria (scant output), polyuria (excessive output), dysuria (painful urination), nocturia (excessive night urination), hematuria (blood in urine), incontinence (involuntary loss).
The NNAAP urinary output skill
Rhode Island Skill 13 — Measures and Records Urinary Output — is one of the five measurement skills, and the recording tolerance is a Critical Element Step.
- Put on clean gloves before handling the bedpan.
- Pour the contents into the graduated measuring container without spilling or splashing.
- Rinse the bedpan and pour the rinse into the toilet.
- Measure at eye level with the container on a flat surface. Holding it up and squinting is the classic failure. If the level falls between marks, round up to the nearest 25 mL.
- Empty the measuring container into the toilet, rinse it, and pour the rinse into the toilet.
- Before recording, remove and dispose of gloves without contaminating yourself and wash hands.
- Record within plus or minus 25 mL of the evaluator's reading.
Weight
Weight is the single most sensitive routine measure of fluid balance and nutritional status a nurse aide takes.
Technique
- Same time of day — ideally early morning, before breakfast
- Same scale every time
- After voiding
- Similar clothing, no shoes, no heavy robe, pockets empty
- Zero the scale before the resident steps on
- Ask the resident to stand in the center of the platform and to stand still, hands off the rails if safe
- Know how to use both a standing balance scale and a non-digital bathroom scale, and how to zero each — the Skills Evaluation expects it
- Chair scales, bed scales, and mechanical-lift scales are used for residents who cannot stand
The NNAAP weight skill
Skill 14 — Measures and Records Weight of Ambulatory Client: verify non-skid footwear before walking to the scale, set the scale to zero before the resident steps on, obtain the weight, wash hands before recording, and record within plus or minus 2 lb (or ±0.9 kg) of the evaluator's reading.
What to report
| Change | Why it matters |
|---|---|
| 2–3 lb gain in 24 hours | Almost certainly fluid retention — heart or kidney failure |
| 5 lb gain or loss in a week | Significant; report regardless of direction |
| 5% loss in a month or 10% in six months | Recognized markers of clinically significant unplanned weight loss |
| Steady downward trend | Malnutrition, depression, dental pain, dysphagia, or undiagnosed illness |
| New edema with weight gain | Report both together — the combination is more informative than either alone |
Height
- Ambulatory resident: shoes off, standing straight against the height rod with heels together, looking straight ahead.
- Bedbound resident: lie flat and supine with the body in alignment; mark the sheet at the top of the head and at the heels, then measure between the marks with a tape measure.
- Height is recorded in inches or centimeters per facility policy and is used with weight to calculate body mass index and to size equipment.
💡 A resident who has "gotten shorter" is a finding, not an error. Loss of height in an older adult can reflect vertebral compression fractures or osteoporosis. Report a measured decrease rather than assuming you mismeasured — then measure again to confirm.
At breakfast a resident drinks a 6 oz cup of coffee, an 8 oz glass of milk, and eats a 4 oz cup of gelatin. What total fluid intake should the nurse aide record?
A resident who weighed 168 lb yesterday morning weighs 171 lb this morning, and her ankles look puffy. What should the nurse aide do?
On the NNAAP urinary output skill, how must the nurse aide read the graduated measuring container?