Pre‐procedure

ActionRationale

1. 1.Show
   Introduce yourself to the patient, explain and discuss the procedure with them, and gain their consent to proceed.
   To ensure that the patient feels at ease, understands the procedure and gives their valid consent (NMC [126], C).
2. 2.Show
   Position the scales for easy access and apply the brakes (if appropriate).
   To ensure that the patient can get on and off the scales easily and to avoid accidents should the scales move. E
3. 3.Show
   Ask the patient to remove their shoes and outdoor garments. The patient should be wearing light indoor clothes only (Action figure 8.13).
   Outdoor clothes and shoes will add additional weight and/or height and make it difficult to obtain accurate measurements. E

Procedure

Measuring weight

1. 4.Show
   Ensure that the scales record zero, then ask the patient to stand on the scales (or sit if using sitting scales). Ask the patient to remain still and check that the patient is not supporting any weight on any object (e.g. the wall or a stick) and that neither of their feet is on the floor.
   To record an accurate weight (NMC [126], C).
2. 5.Show
   Note the reading on the scale and record it immediately. Check with the patient that the weight reflects their expected weight and that the weight is similar to previous weights recorded. This may require conversion of weight from kilograms to stones and pounds or vice versa.
   To check that the weight is correct. If the weight is not as expected then the patient should be reweighed. E

Measuring height

1. 6.Show
   Ask the patient to stand straight with heels together. If the stadiometer is wall mounted, the heels should touch the heel plate or the wall. With a freestanding device, the person's back should be toward the measuring rod.
   To ensure that the patient is standing upright. If the person does not have their back against the measuring rod then the measuring arm may not reach the head. E
2. 7.Show
   The patient should look straight ahead and with the bottom of the nose and the bottom of the ear in a parallel plane. The patient should be asked to stretch to reach maximal height.
   To ensure an accurate height is measured. E
3. 8.Show
   Record the height to the nearest millimetre.
   To record an accurate measurement of the patient's height (NMC [126], C).

Estimating height using ulna length (only use this method if not possible to measure height in the usual way; Silva and Figueira [170])

1. 9.Show
   To estimate the height of a patient from ulna length, ask the patient to remove any long‐sleeved jacket, shirt or top.
   To be able to access the patient's left arm (if possible) for measurement purposes. E
2. 10.Show
   Measure between the point of the elbow (olecranon process) and the midpoint of the prominent bone of the wrist (styloid process), on the left side if possible (Action figure 8.14).
   To obtain a measurement of the length of the ulna. The measurement is taken on the left arm as this is usually the non‐dominant arm. E
3. 11.Show
   Estimate the patient's height to the nearest centimetre, using a conversion table (see Figure 8.12).
   To estimate the patient's height (BAPEN [14], C).

Estimating BMI from mid‐upper arm circumference (MUAC)

1. 12.Show
   To estimate BMI from the MUAC, ask the patient to remove any long‐sleeved jacket, shirt or top.
   To be able to access their left arm (if possible) for measurement purposes (BAPEN [14], C).
2. 13.Show
   Measure the distance between the top of the shoulder (acromion) and the point of the elbow (olecranon process), on the left side if possible (Action figure 8.15a). Identify the midpoint between the two points and mark the arm (Action figure 8.15b).
   To obtain the mid‐point of the upper arm. The measurement is taken on the left arm as this is usually the non‐dominant arm. E
3. 14.Show
   Ask the patient to let the arm hang loosely by their side and, with a tape measure, measure the circumference of the arm at the midpoint (Action figure 8.16).
   To obtain an accurate measurement of the MUAC. E
4. 15.Show
   Document the measurement.
   To record an accurate measurement of the MUAC (BAPEN [14], C).
5. 16.Show
   Estimate the patient's BMI:

   • If MUAC is <23.5 cm, BMI is likely to be <20 kg/m²
   • If MUAC is >32.0 cm, BMI is likely to be >30 kg/m² (BAPEN [15])
   To estimate the patient's BMI (BAPEN [15], C).

Measuring waist circumference

1. 17.Show
   To measure waist circumference, ensure that a tape of adequate length is available. The correct position for measuring waist circumference is midway between the uppermost border of the iliac crest and the lower border of the costal margin (rib cage). The tape should be placed around the abdomen at the level of this midway point and a reading taken when the tape is snug but does not compress the skin (Action figure 8.17).
   To obtain an accurate measurement of the waist circumference. Can be used to assess risk of heart disease, diabetes and some cancers (National Obesity Forum [106], C).

Post‐procedure

1. 18.Show
   Document height and weight, or estimated BMI, in the patient's notes.
   To record the accurate measurement of the patient's height and weight (NMC [126], C).