Nor-Adrenaline (Nor-Epinephrine) – 24-Hour Urine Test

The Nor-Adrenaline (Nor-Epinephrine) – 24-hour urine test measures the amount of noradrenaline excreted in urine over a complete 24-hour period. Noradrenaline, also known as norepinephrine, is a catecholamine produced mainly by sympathetic nerve endings and, to a lesser extent, by the adrenal glands located above the kidneys. It functions as both a neurotransmitter and a hormone and helps the body respond to physical or emotional stress.

During a stress response, noradrenaline can increase alertness, constrict certain blood vessels and contribute to an increase in blood pressure. After circulating in the body, it is broken down into metabolites and eliminated through urine. Measuring urine collected over 24 hours provides information about catecholamine production across an entire day rather than at one isolated moment.

The test is most commonly used as part of the investigation for uncommon catecholamine-producing tumours, particularly pheochromocytoma and paraganglioma. It may also be used with other catecholamine measurements when evaluating selected patients with unexplained or episodic hypertension, palpitations, excessive sweating, severe headaches or other symptoms suggestive of excessive catecholamine production.

This test cannot independently confirm or exclude a tumour. The result must be interpreted alongside symptoms, medicines, medical history, metanephrine measurements, imaging and other investigations recommended by the treating specialist.

What Is Noradrenaline?

Noradrenaline belongs to a group of naturally occurring chemicals called catecholamines. The major catecholamines include adrenaline, noradrenaline and dopamine. These substances are involved in the body's fight-or-flight response and help regulate blood pressure, heart function, circulation and the response to stress.

Noradrenaline is released primarily from sympathetic nerve endings. When the body encounters exercise, pain, fear, low blood glucose, cold exposure or another physiological challenge, noradrenaline release may increase. Its effects include narrowing certain blood vessels and helping maintain or raise blood pressure.

Because catecholamine concentrations can change rapidly, a single blood measurement may be affected by posture, anxiety, pain and the stress of sample collection. A properly collected 24-hour urine sample integrates secretion over a longer period and may help identify sustained or intermittent overproduction.

Why Is the 24-Hour Urine Noradrenaline Test Performed?

A physician, endocrinologist, cardiologist or oncologist may request this test when catecholamine excess is suspected. It is generally used as part of a broader evaluation rather than as a routine screening investigation for everyone with high blood pressure.

Pheochromocytoma

Pheochromocytoma is a rare tumour arising from chromaffin cells, usually within an adrenal gland. Some pheochromocytomas release excessive amounts of catecholamines, which may produce episodic or persistent hypertension, severe headaches, sweating, tremors, anxiety-like symptoms and a rapid or forceful heartbeat.

Urinary noradrenaline may be elevated in a catecholamine-producing pheochromocytoma. However, biochemical investigation commonly includes plasma-free metanephrines or urinary fractionated metanephrines because catecholamines can be released intermittently while their metabolites may provide a more consistent marker.

Paraganglioma

Paragangliomas arise from related neuroendocrine tissue outside the adrenal glands. Some produce catecholamines, whereas others do not. Functional paragangliomas may release predominantly noradrenaline or other catecholamines depending on their location and biochemical characteristics.

A noradrenaline result may support the investigation, but tumour localisation requires appropriate imaging after biochemical findings and clinical circumstances have been reviewed by a specialist.

Unexplained or Episodic Hypertension

The test may be considered when blood pressure is extremely high, difficult to control or associated with sudden attacks of headache, sweating and palpitations. Most hypertension is not caused by a catecholamine-producing tumour. Therefore, testing is usually reserved for patients whose symptoms, examination, family history or imaging results create a meaningful clinical suspicion.

Symptoms That May Lead to Testing

Symptoms associated with catecholamine excess can vary and may occur continuously or in sudden episodes. They may include:

• Severe or recurrent headaches.
• Episodes of excessive sweating.
• Rapid, pounding or irregular heartbeat.
• Persistent or episodic high blood pressure.
• Trembling, pallor or flushing.
• Chest or abdominal discomfort.
• Anxiety-like episodes or a feeling of impending danger.
• Unexplained weight loss.
• Nausea, weakness or breathlessness.

These symptoms are not specific to pheochromocytoma or paraganglioma. They may occur with anxiety disorders, thyroid disease, heart rhythm disorders, medication effects, low blood glucose and many other conditions. A qualified doctor should determine whether catecholamine testing is appropriate.

Who May Need This Test?

The test may be considered for a patient with characteristic symptom episodes, an adrenal mass discovered during imaging, a previous catecholamine-producing tumour, a hereditary syndrome associated with pheochromocytoma or paraganglioma, or a close family history of these tumours.

It may also be used during follow-up after treatment to look for biochemical evidence of persistent or recurrent disease. Follow-up schedules and the most appropriate biomarkers are determined by the treating specialist.

Sample Requirements

All urine passed during a complete 24-hour period must be collected in the container supplied or approved by the laboratory. Depending on the laboratory protocol, the container may contain a preservative. Patients must not discard the preservative, rinse the container or transfer it into another vessel.

The accuracy of the result depends heavily on complete collection. Missing even one urine sample may make the result unreliable and may require the collection to be repeated.

How to Collect a 24-Hour Urine Sample

1. Choose a collection day on which every urine sample can be collected conveniently.
2. On the first morning, empty the bladder into the toilet and note the exact time. Do not add this first urine to the container.
3. Collect every urine sample passed after that time, throughout the day and night, in the supplied container.
4. At exactly the same time the following morning, empty the bladder and add this final urine to the container.
5. Keep the container stored exactly as instructed by the laboratory, commonly refrigerated or in a cool place.
6. Return the complete collection promptly and provide the collection start and finish times.

If any urine is missed, spilled or accidentally discarded, contact the diagnostic centre. Starting a new 24-hour collection may be necessary. The laboratory may also record the total urine volume before analysing an aliquot.

Preservative Safety

Some collection containers contain acid or another chemical preservative. Patients should avoid direct contact with the preservative and should not urinate directly into a container containing acid. A clean collection vessel may be provided so the urine can be transferred carefully into the main container. Keep the container away from children and follow all safety instructions supplied by the laboratory.

Preparation for the Test

Preparation requirements can vary according to the analytical method. Certain foods, beverages, medicines, supplements, nicotine, alcohol, caffeine, strenuous exercise and emotional stress may influence catecholamine measurements. Patients must obtain specific preparation instructions from Focus Diagnostics and their treating doctor before beginning collection.

Do not stop prescription medicine independently. Some medicines can significantly affect blood pressure or health if discontinued abruptly. The doctor will decide whether any medicine should be temporarily withheld and whether this can be done safely.

Medicines and Substances That May Affect Results

Potential interferences may include selected antidepressants, decongestants, stimulants, bronchodilators, levodopa, certain blood-pressure medicines, nicotine, caffeine and other substances. Analytical interference differs between laboratory methods, so patients should provide a complete list of prescription medicines, non-prescription products, vitamins and herbal supplements.

Acute illness, pain, strenuous exercise, sleep deprivation and severe emotional stress may also increase catecholamine release. When clinically appropriate, collection should be performed during a stable period and according to the doctor's instructions.

How Is the Test Analysed?

After the complete collection is returned, the laboratory records or confirms the total urine volume. A representative portion is analysed using a validated method such as high-performance liquid chromatography or liquid chromatography coupled with mass spectrometry, depending on the laboratory.

The result may be reported as the total amount of noradrenaline excreted during 24 hours. Units and reference intervals vary between laboratories and analytical methods. Patients should use the reference interval printed on their own report.

Understanding the Test Result

The result is interpreted according to the degree of elevation, quality of collection, symptoms, medicine use and associated biochemical findings. One borderline or mildly elevated result does not automatically indicate a tumour.

Elevated Urinary Noradrenaline

A marked increase may be associated with a catecholamine-producing pheochromocytoma or paraganglioma. Increased values may also occur because of physiological stress, acute illness, strenuous exercise, obstructive sleep apnoea, certain medicines, nicotine or collection-related factors.

If the result is elevated, the doctor may review preparation and possible interfering substances before recommending repeat testing or additional measurements. Biochemical confirmation is generally obtained before dedicated tumour-localisation imaging is pursued.

Normal Urinary Noradrenaline

A result within the reference interval makes clinically significant noradrenaline overproduction less likely but does not always exclude intermittent secretion or a tumour that produces different catecholamines or metabolites. The sensitivity of the investigation depends on the tumour, test method, collection accuracy and other factors.

If clinical suspicion remains high, the doctor may recommend plasma-free metanephrines, urinary fractionated metanephrines, repeat collection or another appropriate investigation.

Borderline Result

Mild elevations are often less specific than pronounced elevations. The doctor may evaluate stress, illness, sleep, collection completeness, medicines and dietary preparation. A repeat test performed under carefully controlled conditions may help distinguish persistent biochemical abnormality from a temporary or false-positive result.

Additional Tests That May Be Recommended

Depending on the clinical findings, related investigations may include:

• Plasma-free metanephrines.
• Twenty-four-hour urinary fractionated metanephrines.
• Urinary adrenaline, noradrenaline and dopamine.
• Urinary vanillylmandelic acid in selected circumstances.
• Serum electrolytes and kidney-function tests.
• Blood glucose or HbA1c.
• Thyroid-function tests when clinically relevant.
• CT or MRI after appropriate biochemical assessment.
• Functional or nuclear-medicine imaging in selected confirmed cases.
• Genetic counselling and testing when hereditary disease is suspected.

Benefits of the 24-Hour Urine Test

Collection over 24 hours accounts for variation in noradrenaline secretion across the day and may capture intermittent increases that are missed by a brief blood sample. The test is non-invasive apart from the practical requirement to collect all urine for a complete day.

When used with metanephrine testing and a well-defined clinical indication, it can contribute useful information to the investigation and monitoring of catecholamine-producing tumours.

Limitations of the Test

The result is vulnerable to incomplete collection, incorrect storage, medicine effects, dietary factors, stress, illness and physical activity. Catecholamine release may also be intermittent. Consequently, normal, borderline or elevated values must all be assessed in the complete clinical context.

The test does not identify the location of a tumour and cannot determine whether a tumour is benign or malignant. Imaging, pathology, biochemical follow-up and specialist assessment may be required.

Nor-Adrenaline 24-Hour Urine Test at Focus Diagnostics

The Nor-Adrenaline (Nor-Epinephrine) – 24-hour urine test is available under the pathology and bio-chemistry department at a listed price of ₹3,250. Patients should confirm the current price, container requirements, preservative instructions, preparation guidelines and expected reporting time while booking.

Collect the approved container before beginning the test. Record the exact starting and finishing times and ensure that every urine sample passed during the collection period is included.

Important Patient Instructions

• Use only the urine container supplied or approved by the laboratory.
• Follow the exact 24-hour collection start and finish times.
• Collect every urine sample passed during the collection period.
• Store the container according to the laboratory's instructions.
• Do not stop medicines unless the prescribing doctor advises it.
• Report any missed or spilled sample to the diagnostic centre.

Medical Disclaimer

This information is intended for general education and does not replace professional medical consultation. The 24-hour urine noradrenaline test cannot independently diagnose pheochromocytoma, paraganglioma or another medical condition. Every result must be interpreted by a qualified healthcare professional alongside symptoms, medical history and other appropriate investigations.