An EET test measures levels of epoxyeicosatrienoic acids (EETs) in blood or urine. These are fatty acid molecules your body produces that help regulate blood vessel function, inflammation, and blood pressure. EET testing is primarily used in research settings to evaluate cardiovascular and kidney health, though it is not yet a routine clinical blood test ordered by most doctors.
The abbreviation “EET” can also refer to esophageal electrophysiology testing, a heart rhythm procedure. Both are covered below.
What EETs Do in Your Body
EETs are produced when your body breaks down arachidonic acid, a type of fat found in cell membranes. They act as signaling molecules in blood vessels, the heart, kidneys, lungs, and brain. Their main job is keeping blood vessels relaxed and open, which helps maintain healthy blood pressure. They also reduce inflammation, protect heart cells from damage during reduced blood flow, and help your kidneys flush out excess sodium.
Your body constantly produces EETs but also breaks them down quickly through an enzyme called soluble epoxide hydrolase (sEH). When that enzyme is too active, EET levels drop and their protective effects diminish. The balance between production and breakdown appears to be a key factor in cardiovascular health.
Why Researchers Measure EET Levels
Lower EET levels have been consistently linked to higher blood pressure and kidney disease in both human and animal studies. People with renovascular disease, for example, tend to have reduced plasma EET levels. In salt-sensitive individuals, the kidneys fail to increase EET production in response to high dietary salt, which contributes to blood pressure spikes. Urine EET levels appear to reflect how well the kidneys are managing sodium, making them a potential window into kidney function.
A large prospective study through the Cardiovascular Health Study found that older adults with type 2 diabetes who had higher plasma EET levels faced a lower risk of heart attack. Conversely, elevated levels of DHETs (the breakdown products of EETs) were associated with a higher risk of ischemic stroke. This suggests that both EET levels and the ratio of EETs to their metabolites carry meaningful health information.
EET levels also shift in response to hormonal conditions. Plasma EET concentrations rise after treatment of primary aldosteronism, a condition where excess aldosterone hormone drives high blood pressure. Researchers believe aldosterone may partly work by suppressing these protective molecules. In kidney disease, increased breakdown of EETs correlates with proteinuria (protein in the urine) and kidney inflammation, and urinary EET patterns have shown promise as predictive markers for certain types of kidney inflammation called glomerulonephritis.
How EETs Are Measured
EET levels are measured using a laboratory technique called liquid chromatography with tandem mass spectrometry (LC-MS/MS). This method separates and identifies individual fatty acid metabolites from a blood, urine, or tissue sample with high precision. It is considered the gold standard for quantifying these molecules because it can distinguish EETs from dozens of structurally similar compounds in the same sample.
In healthy volunteers, plasma EET concentrations average around 106 nanograms per milliliter, though values vary between individuals. There are no widely established clinical reference ranges the way there are for cholesterol or blood sugar. This is one reason EET testing remains largely in the research domain rather than in routine medical practice. The equipment required is specialized and typically found in academic laboratories or clinical trial facilities, not standard hospital labs.
Is This a Test Your Doctor Would Order?
Not currently. EET measurement is used in clinical research trials and population studies exploring cardiovascular risk, kidney disease progression, and diabetes-related complications. It has demonstrated value as a biomarker, particularly for understanding why some people with diabetes develop heart attacks or strokes while others do not. However, it has not yet been adopted into standard clinical guidelines for diagnosing or monitoring any specific condition.
If you came across the term “EET test” in a research study or from a specialist, it likely refers to this biomarker measurement. No specific fasting protocols have been established for EET blood draws, though general best practices for blood testing (fasting 10 to 12 hours, drinking only plain water, continuing regular medications unless told otherwise) would typically apply.
Transesophageal Electrophysiology Testing
“EET” sometimes refers to a different procedure entirely: transesophageal electrophysiology study, used to diagnose heart rhythm problems. This is a noninvasive cardiac test where a thin catheter (about 2 millimeters in diameter) is passed through the mouth and into the esophagus, which sits directly behind the heart. Because of that proximity, electrodes on the catheter can pick up the heart’s electrical signals with exceptional clarity, particularly the small signals from the upper chambers that surface ECGs sometimes miss.
The catheter can also deliver programmed electrical pulses to the heart, which allows doctors to trigger and then identify abnormal rhythms in a controlled setting. This makes it useful for diagnosing conditions like sick sinus syndrome (where the heart’s natural pacemaker malfunctions), supraventricular tachycardia (abnormally fast rhythms originating above the ventricles), and other conduction abnormalities. It can also serve as a temporary pacemaker for patients with dangerously slow heart rates in urgent situations, or substitute for a treadmill stress test in patients who cannot exercise.
Before the procedure, a numbing gel is swallowed to reduce discomfort as the catheter passes through the throat. The test itself involves the doctor gradually adjusting the timing and pattern of electrical pulses while monitoring the heart’s response. Compared to invasive electrophysiology studies, where catheters are threaded through blood vessels into the heart itself, the transesophageal approach carries less risk and requires no sedation or vascular access.