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Body composition means substances forming our human body. There are various approaches to body composition analysis, including histological one and anatomical one. Further, there are Two-compartment model and Multi-component model. Multi-component model is divided again into Atomic model, Molecular model, Cellular model, and Tissue system model.

Two-compartment model, a traditional body composition model, divides our human body into fat and fat-free mass (Siri and Brozek). This model is based on assumption that density values of fat-free mass, potassium, and water are stabilized and constant.
However, clinically detailed and accurate analysis of body composition has been highlighted in these days. In addition, many clinical studies have demonstrated that two-compartment model has limited applicability. In other words, it cannot be generally applicable by ethnic groups, ages, and gender. As a result, an alternative model called multi-component model has been proposed. Multi-component model is highly useful in analyzing body composition. This model is based on assumption that body composition data at a specific level are useful for explanation of body composition for different parts due to biological homeostasis. Therefore, clinical data on a specific sample help us analyze different body parts.

Hydrostatic Weighing : This method based on Archimedes principle determines the amounts of body fat and non-fat components. First, your dry weight and underwater weight are measured. Then, apply the water density to the following Formula 1 to get mean body density.

Mean body density calculated according to Formula 1 is used to determine the amount of fat tissues according to the Siri equation as follow (mean density of fat tissues: 0.9 g/cc, mean density of non-fat tissues: 1.10 g/cc);

DEXA : DEXA is an abbreviation for "Dual Energy X-ray Absorptionmetry". DEXA data can be used for analysis of body composition. DXA uses two x-rays of different energy levels. Since the subject's attenuation coefficient is non-linear to radiant energy applied, the effect of a specific component can be removed from data obtained by passing x-rays through the subject. In general, to obtain better signal-to-noise level, there should be obvious difference between atomic numbers of target material and other materials. DXA is mainly used to determine the strength of your bone for diagnosis of osteoporosis. DXA is used to remove the effect of soft tissues when measuring the density of bone.

When voltage (E) is applied to biological tissues, current (I) flows through them. Complex ratio of voltage to current is called impedance. Body impedance means impedance measured at wrists and ankles with use of surface electrodes

The following figures show principles of body impedance analysis to get segmental body composition. Use of various combinations for current input and voltage output parts results in easy measurement of impedance between body, both legs, and both arms.

Traditional hydrodensitometry allows analysis of two body components for the whole body. However, DXA is highly useful for accurate analysis of body composition for specific parts, such as body, both legs, and both arms. Accordingly, concurrent clinical use of body impedance values and segmental body compositions (such as DXA) enables more accurate analysis of body composition for a specific body part.

The frequency of 50 kHz does not have any clinical grounds. The frequency value has been traditionally used and the electric current is determined from the perspective of safety. The frequency level used in single -frequency analysis method does not have any clinical meanings or grounds. Efforts have been made to overcome the single-frequency analysis method's problem through frequency characteristics and models of body impedance. If the frequency level is increased or decreased, body impedance is converged into the value of resistant components.

The Fricke model explains changes of body impedance according to frequency levels, while the Kohl-Kohl distribution system shows generalized pattern of the Fricke model. Also, in order to improve the relationship between impedance model and body composition, measurement of impedance at frequency of lower than 1 kHz and frequency of higher than 100 kHz was attempted to get the impedance close to converging values at both ends, which solves the problem of being unable to apply electric currents at the frequencies of zero and infinity into the body and enables more practical analysis of actual body composition. In other words, body fluid containing electrolytes allow flow of current. Body impedance measures body water on the basis of such simple principle. Most BIA devices employ alternating currents of 50 kHz. Currents at this frequency level are able to pass through most extracellular components and some currents penetrate into cells. Low frequency  (1kHz ~ 5 kHz) is not able to pass through cells due to inherent property of cellular membrane.
So, the impedance is affected only by extracellular components. In addition, currents of high frequency (100 ~500 kHz) are able to penetrate cellular membrane and so, the impedance is measured as the sum of intracellular and extracellular components. In short, multiple frequency method overcomes the problem of the single-frequency method and enables measurement of body water content and intracellular and extracellular components.

In order to analyze body composition of each part, 8-point electrodes method (also called Segmental BIA) should be used. For stabilized analysis, electrodes should be necessarily used. In general, disposable electrodes have been widely used. However, as bioelectrical (biopotential) measurement technology has been employed for many medical devices (e.g., EKG), clip-style electrodes have been introduced to solve the inconvenience of such disposable electrodes. Our BCA series use clip electrodes of which safety and effectiveness have been proved.

-Graphic User Interface : Graphic icons for convenient use of program, display of examination results in
-graphs and charts.
-Database sharing through network : If examination room is separated from doctor's office, examination
-results can be shared through network. Further, use of dual monitors will allow patient and doctor to see the
-same image at the same time, which will increase patient's understanding.
-Comprehensive foods list (about 700 foods) : Comprehensive list of foods that can be easily found at
-restaurants or grocery markets is provided to allow easy calculation of caloric intake. This list is highly
-useful for providing dietary prescription and explaining the relationship of adult diseases
-(hypertension, hyperlipemia , diabetes, and arteriosclerosis) and constitutions.  
-Database of patient information and examination records : Patient information and examination records
-can be maintained as database, reducing the burden of paper works.
-Normal standard value setting : You can set normal standard values (BMI, WHR, body fat, body water,
-and proper body weight) for body composition analysis.