Performing a BIA test

Should the test subject lie down to be tested?

Yes. All research has been performed with the subject lying flat with legs apart and arms not touching the body, therefore it is recommended that the test subject lie down to be tested.

What side of the body is used for BIA testing?

The right side of the body is commonly used for BIA testing. However, the left side of the body may be used if necessary. It is important to be consistent and use the same side on a test subject for repeatability.

Can you feel the test while it is being performed?

No, the current passed through the body is so small that it is unlikely it will be felt at all.

How long does it take to perform a BIA test on a subject?

Typically, the test will take approximately five minutes, including entering the information into the software and generating the report.

What electrodes can be used for testing?

RJL Systems, Inc. (RJL) suggests that the tests be performed using the adhesive electrodes supplied by them. RJL cannot guarantee accurate test results acquired by using other electrodes.

Do I have to use new electrodes for every test subject?

Yes, for accuracy, and above all, for sanitary reasons, new electrodes should be used for each test performed.

Can the age of electrodes affect results?

Yes, RJL electrodes have a shelf life of 14 months. Expired electrodes will produce inaccurate results. As well, if electrodes are not kept in a sealed bag or container, they can dry out and also produce inaccurate results.

Is there anything particular that the test subject should do prior to being tested with the RJL Analyzer?

The test subjects body should be dry; no fever should be present, and should not be chilled or cold. Please review “Subject Protocol” on the “Electrode Placement” card.

Could very dry or very oily skin affect the BIA readings?

Yes. Good contact between the skin and electrodes must be made for accurate results. If a person’s skin is oily, wipe the area with an alcohol swab before positioning the electrodes. If the skin is very dry, use an electrode gel.

Do women have to remove their nylons before testing?

Yes, the adhesive electrodes must make direct contact with the skin for an accurate measurement.

Will jewelry affect the BIA test?

No, there will be no effect on the BIA test provided the jewelry does not interfere with electrode placement. However we recommend that all jewelry be removed.

Do pins or rods in a subject’s arms or legs affect the BIA readings?

If they are metallic and within the signal path, yes, they can impact the readings. If the person only has pins or rods on one side of the body, test the person on the opposite side. If the implants are bilateral, the person can still be tested, with the understanding that the estimated body composition values may not be accurate. HOWEVER, serial measurements would allow you to track which direction each compartment is trending, even if you didn’t have any confidence in the specific value reported.

Can people with implanted devices such as defibrillators, pacemakers, medication pumps, etc be tested with the RJL analyzers?

There are two issues to consider in attempting to answer this type of question:

  1. Could the other device interfere with the RJL Analyzer? 

    For us to answer the first question is relatively straightforward. The presence of an implanted device in the body will likely have a small impact on the measured resistance and reactance values, which will, in turn have a small impact on the estimated body composition. However, this effect should be consistent between tests, so even if the body fat estimate (for example) is offset by the implant, if subsequent tests show the estimated body fat decreasing, you can be confident that the body fat is, in fact, decreasing.Implanted Cardioverter Defibrillators (ICDs) are a special category of device. Because they work by delivering a large voltage to the heart, there is a chance that the BIA may be damaged if it is connected when the Defibrillator discharges.

  2. Could the RJL Analyzer interfere with the other device? 

    You will need to ask the manufacturer of the other device. Give them the link to this page, and tell them that if they need more information, they can email support@rjlsystems.com or contact us by phone.RJL Systems’ analyzers measure impedance using a 50 kHz sinusoidal signal that adheres to the requirements of IEC 60601-1:2007 for Patient Auxiliary Current in a Type BF applied device.


Will medication affect the reliability of the BIA test?

Changes in the results may come from medications, disease and nutritional status. BIA results quantitatively illustrate all of these factors and conditions. That’s what BIA is all about!

Can obese or emaciated test subjects be tested with the RJL analyzers?

Yes, and serial testing will reflect changes in a person’s body composition.

Can pregnant women be tested with the RJL analyzers?

No. None of the equations provided by RJL Systems have been validated for use during pregnancy, and with all of the changes that occur in the woman’s body and in the developing child, you could not be confident in the accuracy of the body composition estimates.

At what age can children be tested?

Equations were developed on children beginning at age 4. However, people of any age may be tested for resistance and reactance results.

Are medical professionals the only people that should perform the BIA test?

No, anyone that has been properly trained can perform the test. Once trained, a technician should be able to retest a patient (changing electrodes) to within a 1% difference in the resistance reading.

What is the average amount charged for a BIA test?

$15.00 charge at a health fair and $25.00 to as high as $150.00 for a test done in other environments. The price will depend on the location and the degree of professional consultation.

How often should the test be performed?

This would depend on your facility and your client. The average professional generally tests every four to six weeks.

How could the RJL analyzer be useful in my everyday practice?

Examples would be a post delivery weight reduction program in an OBGYN setting or lifestyle change in a wellness setting.

Are there any CPT codes I can use to get insurance reimbursement for doing a BIA test?

At this time, there are no CPT codes specific to BIA. That being said, we have gotten reports from some of our customers of codes that they had been able to get reimbursement under. We have prepared a list of these codes – Click to View

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