BCM (ATM) and ECM
In addition to body compostion parameters (FM, FFM, TBW, ECF, ICF), outside the United States, ImpediMed's DF50 also reports Body Cell Mass (BCM), also called Active Tissue Mass (ATM) and Extracellular Mass (ECM). Within the US, the company was informed by the FDA that no predicate device has been approved which reports these parameters. In order to report BCM and ECM within the US, therefore, the company will have to file for additional FDA clearence. Until then, ImpediMed has taken the position that it will not promote nor display in its devices these non-FDA cleared parameters. Other bioimpedence device reporting BCM and/or ECM are doing so off-label.
Active tissue mass (Body cell mass), Extracellular mass (ECM) form part of the extended body compartment model used by some researchers and practitioners. Some practitioners have found that combinations of the basic body composition compartments can be useful when defining and documenting the change in the metabolically active areas of the body.
Active Tissue Mass or Body Cell Mass is the total mass of all the cellular elements in the body which constitute all the metabolically active tissue of the body. The ATM includes muscle tissue, organ tissue, and intracellular fluid. In the normally nourished individual, muscle tissue accounts for approximately 60% of the ATM, organ tissue accounts for 20% of ATM, with the remaining 20% made up of red cells and tissue cells. The ATM also contains the large majority (98-99%) of the body's potassium. These practitioners believe that ATM provides a way to document the nutritional status of an individual and track the calorific requirements of that person through the calculation of basil metabolic rate (BMR). BMR is a reported parameter in the DF50 Body Compostion Software.
The metabolically inactive components of body compostion then is made up of skeletal mass and extracellular fluid (ECF). A review of the literature shows that skeletal mass is generally assumed to represent about 12% of person's ideal body weight.
Practitioners within the US interested in these parameters can review published and public domain literature on these topics.
