BIS detects medically meaningful fluid shifts as low as 36 ml in a limb.1
Bioimpedance spectroscopy (BIS) technology
Bioimpedance spectroscopy (BIS) is the only noninvasive, low-cost technology that can accurately measure a patient’s total body water, extracellular and intracellular fluid volumes in a clinical setting. This detailed data can help healthcare professionals with early detection, assessment and interventions for chronic conditions.
95% reduction in lymphedema progression using BIS for early detection combined with at-home intervention.2
A combination of BIS measurements offers the best option to manage heart failure.3
ImpediMed and our subsidiaries pioneered the use of BIS technology, producing the first commercially available BIS devices in 1990. Our patented, clinically proven BIS technology measures impedance at 256 different frequencies, from 3 kHz to 1000 kHz, and uses validated mathematical models to determine three pure resistance values in the body:
- Resistance at zero frequency, which translates to the free fluid outside of the body’s cells
- Intracellular resistance, which translates to the intracellular fluid inside the body’s cells
- Resistance at infinite frequency, which translates to the total body water including fluid inside of the body’s cells
These values form the foundation of all of the tissue and fluid output measures produced by ImpediMed’s BIS products.
Limitations of other systems
In contrast, other bioimpedance systems use multi-frequency bioimpedance analysis (MF-BIA). Unlike BIS, MF-BIA devices typically measure impedance at 2-6 different frequencies and are unable to determine the pure resistance values at zero and infinite frequencies. MF-BIA relies instead on equations applied to single-frequency impedances to create readings of the patient’s fluid levels. None of these provides a pure quantification of the different fluid compartments in the body.
- Ward L. Is BIS ready for prime time as the gold standard measure? Journal of Lymphoedema, 2009. 4(2): p. 52-56.
- Ridner SH, et al. A randomized trial evaluating bioimpedance spectroscopy versus tape measurement for the prevention of lymphedema following treatment for breast cancer: interim analysis. Ann Surg Oncol 2019; https://doi.org/10.1245/s10434-019-07344-5
- Weyer S, et al. Bioelectrical impedance spectroscopy as a fluid management system in heart failure. Physiol Meas, 2014. 35(6): p. 917-30.