Did you know? Just because your leakage meter reports a test failure, it doesn’t mean that the probe is at fault. Leakage test failures can be confusing. This post will help you and your end-users understand just what’s going on with leakage test failures and how to troubleshoot several scenarios.
TEE probe leakage testing
The concept of TEE probe leakage testing is related to identifying a break in the probe’s physical integrity (on the distal tip, bending section, or insertion tube) that COULD allow a micro-shock condition to present itself. Given the statistical probability of a micro-shock scenario not occurring, there are other, very important, reasons to perform TEE probe leakage testing.
If a break in a TEE probe’s physical integrity exists, the cut, hole, or void could
- Harbor bacteria leading to cross-contamination, or
- Allow harsh chemical disinfectants to enter the probe and be subsequently discharged, from the probe into a patient, during its next use, or
- Cause catastrophic internal electronic failures that can result in the need to replace the probe.
Fluid Invasion
If there is a break in physical integrity, and the probe is immersed in disinfectant or processed in an automated system, the chemical disinfectant will flood the probe. Once inside a TEE probe, chemical disinfectants can corrode the electronics in a matter of hours, causing massive damage. If a fluid invaded probe is energized on a scanner, the probe’s sensitive electronics might be irreparably damaged. The scanner itself might also require a costly repair.
Error codes, such as 005, 025, and “setup error” displayed on the scanner are often indications of a probe that has been fluid invaded.
What happens during a TEE probe leakage test?
Whether your end-users are using a Fluke ULT800 or BC Group ULT2020 (the two most common meters in-use), it’s possible for to encounter false-positive leakage test results.
TEE leakage meters perform two tests as part of the full testing protocol: a bath (or conductivity) test and the leakage test.
A bath, or conductivity, test confirms that 1) the proper test lead of the leakage meter is immersed in a test liquid and 2) that the test liquid has enough particulates to adequately conduct electricity. If this test fails, or an error message occurs during this test, the issue IS NOT PROBE-RELATED.
To successfully pass the leakage test, the value of leakage, in microamps (uA), must be both, above a lower threshold and below an upper threshold. The lower threshold confirms that
- The probe is properly connected to the meter’s test adapter(s), and
- The probe is immersed deeply enough in the test liquid.
Test Failed: Leakage Too Low
If end-users encounter a “Leakage Too Low” error message, while using the BC Group meter, the issue IS NOT PROBE-RELATED. The Fluke meter uses a very slowly flashing red “fail” LED to indicate the same. In this scenario, problems with the set up or connectivity are indicated. Possible sources could be
- Failed or intermittent lead wires
- Poor connectivity between the probe and the meter’s test adapters
- The probe not being immersed, or immersed deeply enough, in the test liquid.
When users encounter Leakage Too Low errors, they SHOULD NOT assume the probe is the problem. Users need to troubleshoot the scenario. Recently, we’ve seen a rise in false positives from customers who use GE TEE probes. Typically, TEE probes are connected to the leakage meter using a single connection. In 2018, GE began requiring the use of two probe adapters, versus one. Without the use of the additional adapter, users WILL intermittently encounter “Leakage Too Low” messages.
Test Failed: Leakage Too High
The upper leakage test threshold is the maximum leakage current permissible (as defined by the meter, not international standards). The Fluke ULT800 uses an upper limit of 185 uA, while the BC Group ULT2020 can be programed with a user-defined values.
If end-users encounter a “Leakage Too High” error message, the issue is most-likely probe related.
Current TEE Probe Leakage Test Limits (as defined by meter manufacturers, not the IEC).
- Philips and Siemens: 185 uA
- GE: 350 uA
We’re here to help
We’ve created a quick reference guide for end users. To request a pdf version of our Leakage Testing Quick Reference Guide, click the button below. The guide can be posted in the testing area to keep users informed and provide troubleshooting tips. When doing so, let us know the manufacturer of your TEE probes. We have separate guides for each.
