We perform Bioelectrical Impedance Analysis (BIA) using a device that measures the patient’s Resistance (Rz) and Reactance (Xc) values. These parameters are of fundamental importance for calculating a wide range of data, which are summarized in a detailed report generated by the professional Bodygram® software from Akern®.

Specifically, the following values are estimated:

• Total Body Water (TBW)
• Extracellular Water (ECW)
• Intracellular Water (ICW)
• Fat-Free Mass (FFM) and Fat-Free Mass Index (FFMI)
• Fat Mass (FM) and Fat Mass Index (FMI)
• Body Cell Mass (BCM) and Body Cell Mass Index (BCMI)
• Body Mass Index (BMI)
• Total Muscle Mass (MM)
• Skeletal Muscle Mass (SMM) and Skeletal Muscle Index (SMI)
• Appendicular Skeletal Muscle Mass (ASMM) and ASMM Index (ASMMI)
• Basal Metabolic Rate (BMR)
• Total Daily Energy Expenditure (TDEE)
• Phase Angle (PhA)

In addition, several graphs are provided to support nutritional assessment, including:

• Biavector®
• Biagram®
• Nutrigram®
• Hydragram®
• Percentile curves of FM and FFM

The test is carried out by applying electrodes that allow the passage of a low-intensity alternating electrical current, which is completely harmless. The current passes through the body’s tissues with different levels of resistance depending on their composition:

• Adipose tissue is less conductive, resulting in higher impedance values.
• Lean tissues, such as muscle cells, contain more water and are better conductors, resulting in lower impedance values.

Body impedance consists of two components measured by the device:

• Resistance (Rz): reflects the passage of electrical current through body fluids (higher fluid levels correspond to lower resistance values).
• Reactance (Xc): reflects the current’s passage through cell membranes, providing an indirect estimate of body cell mass.

The ratio between Resistance and Reactance (Rz/Xc) yields the Phase Angle (PhA), expressed in degrees, which reflects active cell mass and is useful for interpreting the subject’s nutritional and hydration status (higher values indicate greater cell mass).

BIA is primarily performed using the tetrapolar method, with two pairs of electrodes (injector and sensor) applied to the dorsal surfaces of the hand and foot on the same side of the body.

To ensure accuracy, the test must be performed under standardized conditions. 

Subjects should:

• Abstain from food or beverages for at least 2 hours prior.
• Avoid moderate-to-intense physical activity for at least 12 hours.
• Empty the bladder within 30 minutes before the test.
• Not be in a febrile state.
   

Additionally, variations in fluid retention during the menstrual cycle must be considered.

BIA can be performed by all individuals except:

• Pacemaker carriers.
• Carriers of neurostimulators, implanted electrodes (intracranial or subdural).
• Individuals with hearing implants.
• Pregnant women.

The data collected by the device and the final report are then analyzed and explained by a qualified nutrition professional.

An example of the report provided to subjects undergoing the analysis is shown below. Typically, this document is sent via email at the end of the test, but a printed version may also be requested.