How to conduct AED regular maintenance test? What is its principle? Are all AED brands applicable?

Like the testing of IEC60601-2-4 performed by all third-party testing laboratories, AED regular maintenance tests use "AED/defibrillator test equipment" or "simulators" to test AEDs. The following descriptions refer to "AED/defibrillator test equipment" as "test equipment".

The testing principle and steps of AED regular maintenance test:

  1. The test equipment sends out ECG signals such as VT (ventricular frequency pulse), VF (ventricular fibrillation) or NSR (normal sinus rhythm), so that the AED to be tested can determine whether an electric shock is required.
  2. The AED to be tested should make a judgment that the VT/VF ECG signal needs to be shocked, and the NSR should not be shocked.
  3. The tester presses the shock button according to the AED's instructions, and the test equipment receives the electrode signal of the AED to be tested. The test equipment will analyze whether the AED shock energy and waveform are normal.

The above tests are in line with the steps and principles of AED's actual use on human body. To put it simply, the test equipment simulates a signal of a real person, and "tricks" the AED into giving an electric shock for first aid. In addition, the test equipment not only sends out the ECG signal that simulates a real person, but is also designed to withstand electric shocks, and then captures the waveform and energy for analysis to determine whether the AED is in a normal state.

Because the test principle of AED regular maintenance test is the same as the way AED rescues real people, it is applicable to AEDs of various brands. It can be seen from the above description that the test process of the AED regular maintenance test does not hack into the internal host of the AED to collect data, nor does it need to disassemble or destroy the AED.   

Is AED Regular Maintenance Test in line with AED manufacturers' regulations?

AED Regular Maintenance Test uses WhaleTeq's field tester DFS200, which is a simulator designed according to the maintenance manual of AED manufacturer*, which simulates the heartbeat of the human body to give the AED and receive electric shocks, which is the same as the principle of AED applied to human first aid. In addition, since AEDs must pass the international standard IEC60601-2-4 before they go on the market, it is stipulated that the frequency of use of AEDs must pass at least 100 to 2,500 electric shocks, so DFS200 can be used to confirm that the AED functions normally and can be used for first aid. The battery provided by the original factory can withstand more than 150 electric shocks or more (depending on the brand). If you have doubts about the battery life test during the warranty period, it is recommended to contact the distributor or refer to the regulations in the maintenance manual.

*Reference: AED manufacturer Zoll's Annual Maintenance Manual

All brands of AEDs offer built-in daily or weekly self-test functions. Why do we still need to conduct regular maintenance test?

AED's built-in self-test provides its owner a very convenient way to check, but it cannot detect all problems, especially the aging of electronic parts.

AED self-test is used to confirm the status of MCU (microcontroller single-chip microcomputer) and firmware, such as whether it is crashed. However, when testing AEDs, more environmental factors should be considered. Actual installation environment, such as high temperature and high humidity, and not been used for many years might cause problems like corrosion, leakage, and aging of electronic parts, but those problems can’t be found out in AED self-test.

In addition, the charging and discharging behavior of the AED, which is related to the state of the storage capacitor, cannot be detected through the AED self-test. Because of the high frequency of AED self-test, if charging and discharging is performed every day or every week, the battery will soon be dead, which is not economical.

However, if the state of the storage capacitor, the charging and discharging control module, and its feedback circuit, which are related to charging and discharging behavior, are damaged, the resulting situation is the deadliest. Common problems include: inability to shock, insufficient shock energy, long charging before shock, abnormal power consumption, etc. These problems cannot be detected through self-test.

The following collects some relevant statistics, many of which are also normal in self-tests, but they fail when needed in an emergency situation. In the actual test cases of WhaleTeq and our clients, there are also cases where the self-test is normal, but abnormalities are found out during regular maintenance test.

According to FDA data in 2015, between 2005 and September 2014, a total of 72,000 users reported abnormalities, and at least 750 deaths may have been caused by AED failure. Therefore, the FDA announced in the same year that AED manufacturers should comply with stricter going-to-market rules.

In Japan, 2014 was the 10th anniversary of the Japanese government's opening of the AED to the public for free use. NHK TV produced a special report, pointing out that a total of 103 cases of AED failure occurred in 9 years, of which 42 were incapacitated, and the worst cases included inability to shock and dead batteries.

What is the maintenance guideline given by the AED manufacturers?

According to the maintenance manual (Service Manual) of AED brand ZOLL (, it clearly defines how to carry out preventive maintenance test.

Excerpt from Chapter 1, 2.0 Preventive Maintenance Test:

Tools Needed

  1. Fluke Impulse 4000 Defibrillator/Pacer Performance Analyzer or equivalent
  2. Universal adapter cable

Test Setup

  1. Turn off the AED Plus unit, remove the cover, and unplug the preconnected electrodes. Keep the electrodes so they can be reconnected later.
  2. Connect the universal adapter cable to the AED Plus unit and to the analyzer.
  3. Turn on the analyzer and set its function to VF (ventricular fibrillation).

Almost all AED manufacturers recommends regular "preventive maintenance tests". After all, electronic equipment may have malfunctions inevitably, and the warranty period does not equal to zero failure. AEDs are life-saving devices in emergencies and it is important to ensure a high availability rate.

The AED regular maintenance test, testing process and principles suggested by WhaleTeq are in line with the manufacturers’ guidelines.

How do other countries conduct AED testing and maintenance?

In developed countries such as Europe and the United States, it is a very popular concept to do testing and maintenance for AEDs. Even manufacturers that specialize in providing such services also use AED test equipment for testing. This service is generally referred to as "AED Preventative Maintenance Service" or "AED On-site Inspection service".

Are there relevant regulations and standards to support the legitimacy of AED regular maintenance tests?

The listing of medical device needs to go through multiple layers of testing. After Class III medical devices are listed, there are requirements for "post-market monitoring". Post-market monitoring also includes product testing, and all testing requires professional and compliant test equipment. Florida state law is more specific, which points out that AEDs should be regularly inspected and maintained. 

In Taiwan, according to Article 51 of Chapter VII of the “Medical Device Act”: “The competent authority may send officials to inspect the facilities and relevant business operations of medical device firms or medical institutions, and may randomly test their medical devices. Those being inspected shall not evade, impede, or refuse. The quantity of test samples to be taken shall be limited to the extent sufficient for use in testing, and receipts shall be given to business operators.”

Those who violate the provisions of Article 51, evade, impede or refuse inspections or random inspections shall be fined. A fine of not less than NT$30,000 but no more than NT. $1000,000 (Chapter 8, Article 70, Paragraph 13).

Also, in article 77 of Chapter IX: “When necessary, the competent authority at any level may designate a subordinate agency or commission a relevant agency (or institution), legal entity, organization, or private institution to conduct all or part of the testing of medical devices. Regulations governing its designation, commissioning, and related matters thereof shall be established by the central competent authority.” That is, medical devices need to be monitored and tested after they are launched.

Who can conduct AED regular maintenance tests?

No, WhaleTeq is a supplier of medical device test solutions. As long as the manufacturer has obtained WhaleTeq or the same level of test equipment, and meets the qualifications of the “Regulations Governing Designation or Commission of Medical Devices Test”, it can provide regular maintenance test services. AED distributors or AED managers can also follow this principle to conduct regular maintenance tests of their AEDs.

WhaleTeq is a professional test solution provider, and all test equipment meet the accuracy and calibration methods required by international standards. We supply to more than 100 third-party laboratories around the world (such as: UL, SGS, TUV), and major medical equipment manufacturers including Philips, GE, Zoll, etc. have purchased the test equipment developed by WhaleTeq for product research and development, with which high quality and precision are guaranteed.

Is it necessary to carry out AED regular maintenance test? What are the benefits?

Just like the medical laboratory of a hospital, regular testing and calibration are also necessary. Ensuring the proper rate of equipment is an important part of AED management. In particular, AED is included in Class III medical equipment, so-called life-saving machine. If any malfunctions occur, a life may be lost, thus regular test and maintenance are required.

As all electronic products, an AED within the warranty period does not equal to zero failure. AEDs are used infrequently, so even if some malfunctions occur, they may not be discovered immediately. It is too late to discover the failure until an emergency situation happens. Only regular maintenance tests may find problems that cannot be detected by self-tests.

Conversely, an AED that is out of warranty does not mean that it cannot be used. However, if it is not tested and continues to be used, the AED owner might also be under tremendous pressure. Discarding AED right after the warranty period is neither economical nor in line with ESG concept.

Double confirmation is assured through self-test and regular maintenance test, so that the AED passed the warranty period can continue to be on duty to guard human life. For AED management units, the cost is relatively lower due to the increase of its service life. This is a win-win-win situation for the owner, the rescuer, and the rescued.

Are self-test and regular maintenance tests both required?

Yes. Self-test is like taking blood pressure at home every day, while regular maintenance test is annual health check. Both are indispensable.

As mentioned in question 3, self-test is a quick and simple way to check AED’s MCU, but because self-test cannot detect all problems, especially the aging of electronic parts, it is necessary to conduct a complete discharge test during regular maintenance test.

In order to keep track of the status of AED at any time, we recommend installing IoT module and uploading daily or weekly self-test results to AED managers. If any abnormality is found, managers can immediately receive SMS notifications sent by IoT module, and dispatch field inspectors right away to deal with the problems.

How often should AED regular maintenance tests be done? Do differences in conditions of AEDs also affect the testing frequency?

Just like the car needs to be inspected regularly, it is recommended to set the regular maintenance test once every six months to a year according to the condition of AEDs. AEDs with a longer service life are greatly affected by external environmental factors, and the frequency of regular maintenance tests should be increased to reduce the probability of unknown situations of AEDs’ failure.