The body composition unit, in addition to its own research programs, provides a variety of tests and services to others. These occasional users of our services fall into three main categories: Academic scientific investigators with research funding from organizations such as the National Institutes of Health, National Science Foundation, American Heart Association, American Diabetes Association, etc. Industry-sponsored investigators conducting research for pharmaceutical companies, device developers and manufacturers, etc. Individuals who are interested in having their body composition, metabolic rate or fitness evaluated. Here is a brief description of the tests and services provided by each lab. The Dual Energy X-Ray Absorptiometry (DXA) laboratory measures the amount of bone mineral in the body and the density of the bone in various locations. These tests are often used to determine risk for osteoporosis. The lab can also measure the amount of fat and fat-free mass in your body. The Chemistry/Tracer Dilution laboratory measures total body water content, extracellular water, and exchangeable sodium and plasma volume using stable isotope tracer dilution methods. The Body Densitometry laboratory measures body composition by determining the volume and weight of your body and using the known densities of fat and non-fat tissues. The classic method involves underwater weighing. A more recently developed method uses air plethysmography. The Whole Body Potassium counter detects naturally-occurring gamma particles emitted by body tissues that contain potassium. Most of the body’s potassium is located in lean tissues such as skeletal muscle. The Imaging (MRI) laboratory uses standard MRI instruments to make regional or whole body images from which the location and volume of many different tissues and organs can be determined. The Anthropometry lab makes physical measurements of circumferences, lengths, and skinfolds from which estimates of body fat, fat-free mass, skeletal muscle, and other quantities can be calculated. The Bioimpedance Analysis lab evaluates body composition by passing a weak electrical current across body tissues and evaluating the impedance to current flow. Links to Energy Expenditure lab for metabolic rate measurements and to Exercise lab for sub-max fitness test. For information on fees and laboratory use, please contact Janine Pangburn, Research Manager at (212)-523-3622.