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Standard operating procedure
Height and weight measurements No: 006D
Height and weight measurements provide the necessary details
to calculate the body mass index of subjects. This information
provides a quantitative measure of obesity in individuals.
Research nurses trained in the method are responsible for recording
height and weight measurements from all subjects.
digital weighing scales
weights (80kg) and height measure standards
ultrasonic height measure
Measurement of height
should be measured without shoes or socks. All hairstyles should
allow the height measure to sit comfortably on their head.
the subject to stand on a level floor with feet parallel and
pointing forwards. Ensure the subject is standing unsupported
and clear of any furniture which may impair the ultrasonic
that the subject is standing as tall as possible. Position
the head in the Frankfurt Plane position (see figure 1), the
lower border of the left orbit and the upper margin of the
external auditory meatus are horizontal.
the measure on the subjects head and ensure the spirit level
the subject to breathe out gently during the measurement.
A bleep denotes the reading has been taken, take the measure
off the subjects head, turn it over and read the height in
the viewfinder. Record the height in centimetres.
you have all the subjects details clearly recorded in the
subjects case report file. The subjects participation in the
procedure is then complete.
Measurement of weight
should be weighed in light clothing; coats, jackets and shoes
should be removed.
the subject to remove excess clothing, overcoats and shoes.
Pockets containing money or keys should be emptied and any
heavy jewellery should be removed.
scales comprises of 2 parts: a platform on which the subject
stands and a hand- held control unit which displays the subject's
weight. Place the weighing scales platform on an even floor
surface. Hold the display unit in your hand or place it on
a nearby table.
the subject is ready to step onto the platform, switch the
scales on and then press the ON button. Select kg`s using
the units button. The viewfinder should display [ 0.0 ], if
it doesn't press the zero button until it is displayed.
the subject to stand very still on the scales platform and
ensure that they are standing free (not leaning on a chair
weight will be displayed in the viewfinder. Record the reading
in kilograms and gram increments. If there is oscillation
between two values, instruct the subject to stand still, if
it still continues to oscillate take the lower reading.
the weight has been recorded instruct the subject to stand
off the platform and re-apply any overclothes and shoes.
you have all the subject's details clearly recorded in the
subject's case report file. The subject's participation in
the procedure is then complete. Switch off the scales.
Calculation of Body mass index
can calculate the BMI measurement automatically. To achieve
this, the following procedure should be performed:
the subject's weight in kilograms. Listen to the bleep of
the scales to denote the weight has been successfully recorded.
and hold the BMI button on the scale's handset for at least
3 seconds. The screen will alter and show you a height of
1.70m. Alter this measurement using the HOLD (up) and SLOW
(down) keys to the subject's own height recording. DO NOT
measure the subject's height on the scales, as this will
not be a true height recording. The subject must stand on
the floor to have their height measured.
you have entered the subject's height, press the BMI button
again. The BMI will automatically be calculated and displayed
in the viewfinder.
with a BMI greater than 30 should be excluded.
- The weighing
scales should be calibrated monthly using the 80kg calibration
weights. Any calibration drifts should be recorded in the
calibration record book. Subsequent subject weights should
be adjusted according to the calibration drift.
measurement is usually more accurate if performed first thing
in the morning.
- The height
measuring device should be calibrated using the set height
calibration rods. A calibration record should be maintained
in the calibration record book. Height measurements should
be taken and adjusted according to the calibration drift.
the weight and height measurement should be recorded twice.
O`Brien E.T et al, (1995), ABC of Hypertension, BMJ Publishing
group, London, 1-34
2. Measuring obesity - classification and description of anthropometric
data, WHO report - consultation on the epidemiology of obesity.
Warsaw 21-23 Oct 1987.