Digitial Chair Scale Operation Instructions - Scale Operation
7
3.2
Using the Body Mass Index (BMI) Function
Body mass index (BMI) is the relationship between weight and height associated with body fat and health risk. It
is a reliable indicator of body fatness for people and even though BMI does not measure body fat directly,
research has shown the BMI correlates to direct measures of body fat. BMI is an inexpensive and
easy-to-perform method of screening for weight categories that may lead to health problems for adults.
Calculating BMI is one of the best methods for population assessment of overweight and obesity. Because
calculation requires only height and weight, it is inexpensive and easy to use for clinicians and for the general
public. The calculation is based on the following formulas:
Calculate BMI by dividing weight in pounds (lbs) by height in inches (in) squared and multiplying by a
conversion factor of 703.
Example: weight = 150 lbs, height = 5’5 (65")
Calculation: [150
÷
(65)
2
] x 703 = 24.96
The standard weight status categories associated with BMI ranges for adults are shown in the following table.
Table 3-2. Standard Weight Status
BMI
Weight Status
Below 18.5
Underweight
18.5 - 24.9
Normal
25.0 - 29.9
Overweight
30.0 and Above
Obese
The following examples show weight ranges, the corresponding BMI ranges and the weight status categories for
a sample height.
Table 3-3. BMI Ranges and Weight Status Example
Height
Weight Range
BMI
Weight Status
5’9”
124 lbs or less
Below 18.5
Underweight
125 lbs to 168 lbs
18.5 to 24.9
Normal
169 lbs to 202 lbs
25.0 to 29.9
Overweight
203 lbs or more
30 or higher
Obese
Use the following steps in determining the BMI.
1. To use the BMI function, weigh the patient as described under Weighing (above) and then press the
BMI
key. If weighing in Lbs, the default height of (5 feet) appears on the display. Use the up or down arrows
to increase the feet height by one foot increments). Press the
BMI
key again to display inches (default is
7.0 inches) Again, use the up or down arrows to increase or decrease the inches height by 0.5"
increments. Press the
BMI
key again to accept the inches value. The final height value will be displayed
ie: 5-07.5 = 5’ 7.5".
2. If you are weighing in Kgs, the default will be 170.0 cm. Use the up or down arrows to increase or
decrease by 0.5 cm increments.
3. To see the patient’s calculated BMI, press the
BMI
key again. The BMI appears.
4. To cancel the BMI display, press the
BMI
key.
