Bioelectrical Impedance Analysis

Interpretation of Results

Once the data is entered into your software program, you can start to interpret the results. The numbers you will see include either pounds or kilograms of body cell mass, extracellular mass, and fat mass. The sum of body cell mass and extracellular mass represents the total fat-free mass.

An individual’s optimal body composition may vary and evaluation is optimally conducted by comparing tests to optimal, healthy baselines. Unfortunately, tests are not often taken prior to the existence of nutrition-related risk. To establish a more general baseline to compare clients to and for our purposes here, we will use a set of "reference" values for men and women. Men carry a mean body fat of approximately 15% while women carry 25% of their weight as body fat. A range of 10-22% of body weight as fat in men and 20-32% in women is considered reasonable.[82] The remainder is expressed as fat-free mass with men carrying about 78-90% of a good body weight as FFM and women carrying approximately 68-80% as FFM. Splitting the FFM out into sub-compartments, we would expect about half of the FFM to be BCM in men. Women generally carry less muscle than men.  In women, this means that their fat-free mass (we are not talking total weight this time) is generally around 45% BCM and 55% ECT. This works fairly well, if the person is at a good weight. If their weight is low, wasting and risk for poor body function may be missed by calculating BCM on current body weight. Therefore, we base BCM goals on height and frame size (ideal body weight). Table 4 shows values for ideal body weight (IBW) according to height and frame size. 

To estimate frame size from an "r" value, wrist circumference can be used in the following calculation: "r" = height (cm)/wrist circumference (cm); For men an "r" value of <9.6 indicates a large frame and >10.4 indicates a small frame; For women an "r" values of <10.1 indicates a large frame and >11.0 indicates a small frame. For more information on this and other anthropometry, visit our sample course, Anthropometry.

 

Table 5 shows goal BCM for height and frame size in non-obese individuals. Fat and ECM weight should change with body weight changes to accommodate additional needs for fluids and calorie excess or deficit. Table 6 shows estimated ranges for ECM and fat.

Table 4. Ideal Body Weights According to Frame Size*  [83] [84]

Ht (inches)

 

Ht (cm)

Men: Ideal Body Weight

Women: Ideal Body Weight

Small Frame

Medium Frame

Large Frame

Small Frame

Medium Frame

Large Frame

60

152.4

95.4

106

116.6

90

100

110

61

154.94

100.8

112

123.2

94.5

105

115.5

61.5

156.21

103.5

115

126.5

96.75

107.5

118.25

62

157.48

106.2

118

129.8

99

110

121

62.5

158.75

108.9

121

133.1

101.25

112.5

123.75

63

160.02

111.6

124

136.4

103.5

115

126.5

63.5

161.29

114.3

127

139.7

105.75

117.5

129.25

64

162.56

117

130

143

108

120

132

64.5

163.83

119.7

133

146.3

110.25

122.5

134.75

65

165.1

122.4

136

149.6

112.5

125

137.5

65.5

166.37

125.1

139

152.9

114.75

127.5

140.25

66

167.64

127.8

142

156.2

117

130

143

66.5

168.91

130.5

145

159.5

119.25

132.5

145.75

67

170.18

133.2

148

162.8

121.5

135

148.5

67.5

171.45

135.9

151

166.1

123.75

137.5

151.25

68

172.72

138.6

154

169.4

126

140

154

68.5

173.99

141.3

157

172.7

128.25

142.5

156.75

69

175.26

144

160

176

130.5

145

159.5

69.5

176.53

146.7

163

179.3

132.75

147.5

162.25

70

177.8

149.4

166

182.6

135

150

165

70.5

179.07

152.1

169

185.9

137.25

152.5

167.75

71

180.34

154.8

172

189.2

139.5

155

170.5

71.5

181.61

157.5

175

192.5

141.75

157.5

173.25

72

182.88

160.2

178

195.8

144

160

176

72.5

184.15

162.9

181

199.1

146.25

162.5

178.75

73

185.42

165.6

184

202.4

148.5

165

181.5

73.5

186.69

168.3

187

205.7

150.75

167.5

184.25

74

187.96

171

190

209

153

170

187

74.5

189.23

173.7

193

212.3

155.25

172.5

189.75

75

190.5

176.4

196

215.6

157.5

175

192.5

75.5

191.77

179.1

199

218.9

159.75

177.5

195.25

76

193.04

181.8

202

222.2

162

180

198

76.5

194.31

184.5

205

225.5

164.25

182.5

200.75

77

195.58

187.2

208

228.8

166.5

185

203.5

*based on "r" values calculated by dividing height in cm by wrist circumference in cm; men: >10.4 = small frame, 9.6-10.4 = medium frame, <9.6 = large frame; women: >11.0 = small frame, 10.1-11.0 = medium frame, <10.1 = small frame. Source: Grant J. Handbook of Total Parenteral Nutrition. Philadelphia: WBSaunders, 1980

Table 5. Ideal Body Cell Mass for Sex, Height, and Frame Size in Non-Obese Individuals

 

Ht (in)

Men

Women

Small Frame

Medium Frame

Large Frame

Small Frame

Medium Frame

Large Frame

60

38.16

42.4

46.64

27

30

33

61

40.32

44.8

49.28

28.35

31.5

34.65

62

42.48

47.2

51.92

29.7

33

36.3

63

44.64

49.6

54.56

31.05

34.5

37.95

64

46.8

52

57.2

32.4

36

39.6

65

48.96

54.4

59.84

33.75

37.5

41.25

66

51.12

56.8

62.48

35.1

39

42.9

67

53.28

59.2

65.12

36.45

40.5

44.55

68

55.44

61.6

67.76

37.8

42

46.2

69

57.6

64

70.4

39.15

43.5

47.85

70

59.76

66.4

73.04

40.5

45

49.5

71

61.92

68.8

75.68

41.85

46.5

51.15

72

64.08

71.2

78.32

43.2

48

52.8

73

66.24

73.6

80.96

44.55

49.5

54.45

74

68.4

76

83.6

45.9

51

56.1

75

70.56

78.4

86.24

47.25

52.5

57.75

76

72.72

80.8

88.88

48.6

54

59.4

77

74.88

83.2

91.52

49.95

55.5

61.05

78

77.04

85.6

94.16

51.3

57

62.7

 

Table 6.  Expected Ranges of Fat and Extracelluar Mass (ECM) for Men Based on Current Body Weight (CBW) in Pounds

CBW

low range fat

high range fat

low range ECM

high range ECM

85

8.5

18.7

33.2

38.3

90

9

19.8

35.1

40.5

95

9.5

20.9

37.1

42.8

100

10

22

39

45.0

105

10.5

23.1

41.0

47.3

110

11

24.2

42.9

49.5

115

11.5

25.3

44.9

51.8

120

12

26.4

46.8

54.0

125

12.5

27.5

48.8

56.3

130

13

28.6

50.7

58.5

135

13.5

29.7

52.7

60.8

140

14

30.8

54.6

63.0

145

14.5

31.9

56.6

65.3

150

15

33

58.5

67.5

155

15.5

34.1

60.5

69.8

160

16

35.2

62.4

72.0

165

16.5

36.3

64.4

74.3

170

17

37.4

66.3

76.5

175

17.5

38.5

68.3

78.8

180

18

39.6

70.2

81.0

185

18.5

40.7

72.2

83.3

190

19

41.8

74.1

85.5

195

19.5

42.9

76.1

87.8

200

20

44

78

90.0

205

20.5

45.1

80.0

92.3

210

21

46.2

81.9

94.5

215

21.5

47.3

83.9

96.8

220

22

48.4

85.8

99

225

22.5

49.5

87.8

101.3

230

23

50.6

89.7

103.5

235

23.5

51.7

91.7

105.8

240

24

52.8

93.6

108.0

245

24.5

53.9

95.6

110.3

250

25

55

97.5

112.5

255

25.5

56.1

99.5

114.8

260

26

57.2

101.4

117.0

265

26.5

58.3

103.4

119.3

270

27

59.4

105.3

121.5

275

27.5

60.5

107.3

123.8

280

28

61.6

109.2

126.0

285

28.5

62.7

111.2

128.3

290

29

63.8

113.1

130.5

295

29.5

64.9

115.1

132.8

300

30

66

117

135.0

Table 7. Expected Ranges of Fat and Extracellular Mass (ECM) for Women Based on Current Body Weight (CBW) in Pounds 

CBW

low range fat

high range fat

low range ECM

high range ECM

85

17

27.2

31.45

37.4

90

18

28.8

33.3

39.6

95

19

30.4

35.15

41.8

100

20

32

37

44

105

21

33.6

38.85

46.2

110

22

35.2

40.7

48.4

115

23

36.8

42.55

50.6

120

24

38.4

44.4

52.8

125

25

40

46.25

55

130

26

41.6

48.1

57.2

135

27

43.2

49.95

59.4

140

28

44.8

51.8

61.6

145

29

46.4

53.65

63.8

150

30

48

55.5

66

155

31

49.6

57.35

68.2

160

32

51.2

59.2

70.4

165

33

52.8

61.05

72.6

170

34

54.4

62.9

74.8

175

35

56

64.75

77

180

36

57.6

66.6

79.2

185

37

59.2

68.45

81.4

190

38

60.8

70.3

83.6

195

39

62.4

72.15

85.8

200

40

64

74

88

205

41

65.6

75.85

90.2

210

42

67.2

77.7

92.4

215

43

68.8

79.55

94.6

220

44

70.4

81.4

96.8

225

45

72

83.25

99

230

46

73.6

85.1

101.2

235

47

75.2

86.95

103.4

240

48

76.8

88.8

105.6

245

49

78.4

90.65

107.8

250

50

80

92.5

110

255

51

81.6

94.35

112.2

260

52

83.2

96.2

114.4

265

53

84.8

98.05

116.6

270

54

86.4

99.9

118.8

275

55

88

101.75

121

280

56

89.6

103.6

123.2

285

57

91.2

105.45

125.4

290

58

92.8

107.3

127.6

295

59

94.4

109.15

129.8

300

60

96

111

132

Click here to go to the next section Notes on Interpreting Obese Patients

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References:

[82] Lohman TG. Body compsition methodology in sports medicine.  Phys Sports Med. 1982;10(12):47-58.

[83] Hamwi G. Changing dietary concepts. In: Danowski TS, ed. Diabetes Mellitus: Diagnosis and Treatment. New York, NY: American Diabetes Association; 1964.

[84] Grant A, DeHoog S. Nutritional Assessment and Support. Fourth Ed. Grant & DeHoog: Seattle, WA, 1991:13-18.


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