In equations: LBM differs from FFM in that cellular membranes are included in LBM although this is only a small percent difference in the body's mass (up to 3% in men and 5% in women)[1] The percentage of total body mass that is lean is usually not quoted – it would typically be 60–90%.
Instead, the body fat percentage, which is the complement, is computed, and is typically 10–40%.
For example, due to the concern of postoperative opioid-induced ventilatory depression in the obese patient, opioids are best based on lean body weight.
For example, the Boer formula is method of choice for LBM estimation to calculate the dose given in contrast CT in obese individuals with BMI between 35 and 40.
Instead of mathematical estimation the actual value of LBM may be calculated using various technologies such as Dual-energy X-ray absorptiometry (DEXA).