4.2 Height, Weight, and Measurements

Weight is one of the most sensitive early indicators of a resident's clinical status. A 3-pound gain overnight in a resident with heart failure can mean fluid overload; a 5-pound loss in a week can signal malnutrition, dehydration, or undetected illness. North Carolina CNAs are expected to weigh residents accurately and report changes early.

Weight

The "Same-Same-Same" Rule

For weights to be comparable across days, every variable must be controlled:

• Same scale (a different scale can differ by 1 – 3 lb)
• Same time of day (usually morning, before breakfast)
• Same clothing (gown only, no shoes, empty pockets)
• After voiding (urine alone can weigh 0.5 – 1 lb)

Reportable Weight Changes

The >2 lb in 24 hours rule is the one most NC CNAs see on the NNAAP exam: it almost always points to fluid retention in a cardiac or kidney patient and requires the nurse to be notified.

Scale Types

Always zero (calibrate) the scale before each use. Document weight in pounds (lb) unless the facility records in kilograms (kg). 1 kg = 2.2 lb.

Height

Ambulatory Residents

1. Resident stands barefoot or in thin socks with heels, buttocks, shoulders, and head touching the upright.
2. Eyes look straight ahead ("Frankfort plane" — ear canal level with the lower eyelid).
3. Lower the height rod to the crown of the head.
4. Read at eye level.

Bed-Bound Residents (supine)

1. Position the resident supine and flat with legs extended.
2. Mark the bed sheet at the top of the head and at the bottom of the heels.
3. Measure the distance between the marks with a tape measure.
4. Record in inches (1 inch = 2.54 cm).

Height rarely changes in adults but is required for BMI and for some medication dosing the nurse performs.

Body Mass Index (BMI)

BMI relates weight to height and helps the nurse and dietitian identify under- or over-nutrition.

CNAs do not calculate or interpret BMI clinically, but the categories appear on the NNAAP written exam.

Abdominal Girth

Abdominal girth (waist circumference) is measured to monitor ascites (fluid in the abdomen, often from liver or heart disease), bowel obstruction, and post-operative swelling.

Procedure:

1. Place the resident supine with the abdomen exposed.
2. Locate the umbilicus — measurements must be taken at the same anatomical landmark every time.
3. Mark the skin lightly with a pen so the next CNA uses the same spot.
4. Slide the tape measure under the resident, keeping it flat and snug — not tight.
5. Read at the end of normal exhalation.
6. Record in inches (or cm per facility policy).

Report: any increase ≥1 inch (2.5 cm) from baseline, sudden bloating, firm or distended abdomen, pain, or changes in bowel pattern.

Other Common Measurements

• Intake and output (I&O): see Section 4.3.
• Calf circumference / leg edema: the nurse may order pitting edema grading (1+ to 4+) which the CNA documents in plain terms ("+2 pitting to mid-shin").

Documentation

Record every measurement with:

• Value and unit (lb, in, mL)
• Date and time
• Site/method (e.g., "chair scale," "abdominal girth at umbilicus, supine")
• Resident position
• Your initials/signature

Never record a measurement you didn't actually take, and never round to make a trend look better. Weight trends are how the facility catches problems early.