bioenergetic testing electrodermal screening bioenergetic scan bioresonance scan EAV ZYTO Asyra QEST4 Vegatest

What Is Bioenergetic Testing? ZYTO, Asyra, QEST4 and Vegatest Explained

Matt

October 23, 2026

10 min read

Key Takeaway

Bioenergetic testing reads how well your skin conducts a tiny current while a device or software presents items. The FDA has cleared some of these devices only for measuring skin response. In a double blind study in the BMJ, electrodermal testing could not tell people with allergies from people without. ResoField measures nothing and is free.

Bioenergetic testing is a family of methods that measure how well your skin conducts a very small electrical current, usually at the hand or at an acupuncture point, while a device or a piece of software presents one item after another: foods, remedies, organs, toxins. The software then ranks the items by how the reading changed. You will see the same idea sold as electrodermal screening (EDS), electroacupuncture according to Voll (EAV), a bioenergetic scan or a bioresonance scan.

In my wife's practice we worked with a QEST4 for years, so I know the routine from the inside. The client holds the handpiece, the screen runs through its tests, and a list comes out at the end. The routine feels convincing. Whether the list says anything true about the body is a separate question, and this article keeps the two apart.

What bioenergetic testing measures

Almost every system in this group measures the same thing: electrical resistance of the skin, also called galvanic skin response. A low voltage circuit runs from an electrode in your hand, through your body, to a probe or a second electrode. The device registers how much current flows.

Skin resistance is real and measurable. It changes with sweat, which is why lie detectors use it. The trouble is everything else that changes it. Stephen Barrett, who ran Quackwatch for decades, wrote that with the classic probe devices "the only thing that influences the size of the number is how hard the probe is pressed against the patient's skin." Whether the skin is moist or dry plays a part as well.

What the devices add is an interpretation. While the reading changes, the device presents an item, either a physical test vial in the circuit or a digital signature in the software, and treats the change as the body's answer to that item. That step is the claim. It is not something the measurement itself shows.

Where it comes from

The method started with Reinhold Voll, a West German physician who practised acupuncture. In 1958, according to Quackwatch, he combined acupuncture theory with skin resistance measurement into his EAV system, and his first transistor model was called the Dermatron. Practitioners pressed a probe on acupuncture points of the hands and feet and read off how much current flowed.

The German physician Helmut Schimmel later helped develop the Vegatest, which measures at one point only while test ampoules sit in the circuit. Computers took over from there. ZYTO, Asyra and QEST4 all automate the same sequence: the client holds or touches an electrode, the software runs through thousands of items and prints a ranked report.

The best known systems compared

System	What touches you	Price (checked October 2026)
ZYTO	Your hand rests on the Hand Cradle	399 to 14,750 dollars up front, plus 50 dollars a month
Asyra	Two brass hand electrodes	No public price; Skepsis estimates 13,000 euros
QEST4	Handpieces, USB or Bluetooth model	No public price, quote after a demo
Vegatest	Hand electrode plus a probe on one acupuncture point	Used devices 299 to 1,400 euros; the current Test Expert Plus has no public price
AO Scan	Nothing by default; software on your own phone or computer	149 dollars a month
Oberon	Headphones	No public price; an older dealer list shows 9,800 to 12,500 euros

AO Scan and Oberon are sold as scans too, but they do not measure skin resistance in the usual way. AO Scan is subscription software, and an Oberon session uses headphones with what the sellers call nonlinear analysis (NLS). I list them because people search for them as the same kind of thing, and because the question you should ask is the same for all six: has anyone shown, under blinded conditions, that the result matches what is really going on?

Two other devices often come up in the same searches. The quantum resonance magnetic analyzer is a cheap sensor from China that prints dozens of reports, and Bio-Well photographs the glow around your fingertips. Each has its own article.

What a bioenergetic scan costs

Practitioners set their own prices. Three published examples:

A US chiropractic practice charges 95 dollars for a ZYTO Balance scan and 125 dollars for an advanced scan (Lemay Chiropractic).
A practice in Bedford, England, charges 80 pounds for a first Asyra consultation of about an hour and a half and 65 pounds for a follow up (Pulse Screening).
A US healing center charges 225 dollars for a first 60 minute QEST4 test and 150 dollars for a 30 minute follow up (Pellegrino Healing Center).

Health insurers generally do not pay for it. A scan often comes with a list of supplements or remedies to buy, so ask before the session what that usually costs on top.

Does bioenergetic testing work?

The best test of a method like this is simple: give it people whose condition is already known, hide that from the operator, and see whether the device finds it.

That is what a team at the University of Southampton did, in a study published in the BMJ in 2001. They tested 15 volunteers with a known allergy to house dust mite or cat dander and 15 without, using the Vegatest. Three Vegatest operators each tested every volunteer in three separate sessions, with allergen samples and distilled water randomly mixed. The result: the electrodermal tests "did not correlate with those of the skin prick tests", no operator did better than another, and no participant was consistently diagnosed correctly. The authors concluded that "electrodermal testing cannot be used to diagnose environmental allergies" (Lewith et al., BMJ 2001).

Later checks point the same way:

Stephen Barrett tested himself 43 times in 10 days with a ZYTO system and called its assessments and recommendations "preposterous and potentially dangerous" (Missouri Medicine, 2017).
The Dutch consumer programme Radar sent one healthy volunteer to two Asyra practitioners on the same day in 2017 and got contradictory results (Radar).
The FDA has cleared devices such as the ZYTO Hand Cradle and the ASYRA only for measuring skin response. In 2023 it sent ZYTO a warning letter for promoting its system for wider uses, including identifying diseases, after an earlier letter in 2015 (FDA warning letter, 21 June 2023).

The makers say much the same in their own words. Asyra writes that its system is not a medical diagnostic device, QEST4 says it is not a diagnostic tool, and Solex says AO Scan is not a medical device. I take them at their word.

So the honest summary is this. The reading is real, the interpretation is not supported. No controlled study I found shows that bioenergetic testing detects an allergy, a deficiency or a disease better than chance.

Is it safe?

The current is tiny, so the physical risk is small. The real risk lies in what you do with the result. A scan can tell you that you are intolerant to foods you can eat perfectly well, or reassure you about a complaint that needs a doctor. For a suspected allergy, the tests that work are a skin prick test or a blood test for specific IgE, done or interpreted by a doctor.

If you decide to have a scan anyway, treat the outcome as a conversation starter, not as a diagnosis, and do not stop a treatment because of it.

Bioenergetic testing and bioresonance

The two overlap and are often mixed up. Bioenergetic testing reads the skin and ranks items. Bioresonance therapy, with devices such as MORA, BICOM and Rayocomp, goes a step further: the device claims to pick up the body's own oscillations, change them and send them back. Many bioresonance devices also have a test mode built on the same skin measurement. If you want the full picture of that second group, read what bioresonance therapy is.

Where ResoField fits

ResoField measures nothing. There is no electrode, no scan and no automatic list. It is a free browser app with libraries for homeopathy, bioresonance and Rife frequencies, client profiles, your own lists and protocols. You choose every remedy yourself, for example with a muscle test or a biotensor, and ResoField keeps track of what you chose and when.

That is a real difference in practice, and I want to be clear about it in both directions. If you want a machine to produce a list for you, ResoField is not that machine. If you already choose remedies yourself and want to organise and broadcast them without buying hardware, it does that for free.

Sources

Prices and product details were checked in October 2026 and can change. This article does not provide medical advice.

FAQ

What is bioenergetic testing?

Bioenergetic testing measures how well your skin conducts a small electrical current while a device or software presents a series of items, such as foods or remedies. The software ranks the items by how the reading changed. It is also called electrodermal screening, EAV or a bioenergetic scan.

What does electrodermal screening measure?

It measures skin resistance, also called galvanic skin response. That reading changes with sweat, skin moisture and how hard a probe is pressed. The step from that reading to a statement about your health is the claim of the method, not something the measurement shows.

Is bioenergetic testing accurate?

Controlled studies say no. In a double blind study in the BMJ in 2001, electrodermal testing could not tell people with a known allergy from people without one, and the authors concluded it cannot be used to diagnose allergies. Repeated self tests with a ZYTO system gave inconsistent results.

How much does a bioenergetic scan cost?

Practitioners set their own prices. Published examples are 95 to 125 dollars for a ZYTO scan in the United States, 80 pounds for a first Asyra consultation in England and 225 dollars for a first QEST4 test. Health insurers generally do not cover it.

Is bioenergetic testing FDA approved?

No device has FDA approval to diagnose disease this way. Some, such as the ZYTO Hand Cradle and the ASYRA, are FDA cleared only for measuring galvanic skin response. The FDA warned ZYTO in 2015 and 2023 for promoting its system beyond that use.

What is the difference between bioenergetic testing and bioresonance?

Bioenergetic testing reads the skin and ranks items. Bioresonance devices such as MORA and BICOM claim to also pick up the body's oscillations, change them and send them back as therapy. Many bioresonance devices include a test mode based on the same skin measurement.

Does ResoField do bioenergetic testing?

No. ResoField has no electrode and no scan. It is a free browser app for libraries, client profiles, lists and protocols, and you choose every remedy yourself, for example with a muscle test or a biotensor.