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Table 1 Showing actual body weight vs lean body mass, adjusted body weight and ideal body weight in kg

From: Initial intravenous immunoglobulin doses should be based on adjusted body weight in obese patients with primary immunodeficiency disorders

  Actual BW (kg) BMI (kg/m2) Lean BW (kg) Adjusted BW (kg) Ideal BW (kg) SCIG/month (g) Serum IgG (g/l)
Pre wt 132 43.1 65.4 92.4 66 57.6 7
Post wt 63 20.6     51.2 9.2
Pre SCIG/kg 0.44 (g)   0.88 0.62 0.87   
Post SCIG/kg 0.81 (g)       
**Pre serum IgG index (IgG/SCIG/kg) 15   7.95 (*predicted) 11.2 (*predicted) 8.05 (*predicted)   
**Post serum IgG index (IgG/SCIG/kg) 11.35   NA NA NA   
  1. * The lean, adjusted and ideal body weights were computed from presurgical weight. The monthly SCIG dose is then expressed as a fraction of body weight as well as each of the calculated body weights. Finally, to account for the differences in steady state serum IgG an index ** was calculated serum IgG/(SCIG/kg) [7]. This is similar to the IgG efficiency index where the weight was static but the dose of SCIG/IVIG was adjusted in lean and obese patients [15]. In this case the dose of SCIG was static while the weight decreased. All measurements were trough levels, just prior to the next dose of SCIG.IVIG. The post bariatric serum IgG/(SCIG/kg) index of 11.35 correlated most closely with the adjusted body weight of 11.2. The IgG index was only calculated for predicted presurgical body weights (LBW, AjBW and IBW). Descriptions: The actual body weight (ABW) is the measured weight. The ideal body weight (IBW) is the most healthy weight for an individual taking into account gender, age and body build. The adjusted body weight (AjBW) in an obese person assumes 25% of fat tissue is metabolically active. In the case of SCIG/IVIG, it is assumed there is distribution to the increased extracellular fluid associated with adipose tissue. Lean body weight (LBW) is calculated when fat is subtracted from the total body weight. Formulae: IBW (women) = 45.5 + 2.3(height over 60 in.), AjBW = Ideal BW + (0.4(Actual BW − Ideal BW)), LBW 2005 (women) = 9.27103Actual BW8.78103 + (244BMI)
  2. LBW lean body weight, AjBW adjusted body weight, IBW ideal body weight, NA not applicable