5-HIAA – Urine 24 Hours

This test measures the levels of 5-HIAA in your urine over 24 hours.

• To detect and monitor carcinoid tumours of the mid-gut
• To evaluate the effectiveness of treatment for carcinoid tumours,
• To diagnose and monitor other conditions that affect serotonin levels,
• To assess the risk of developing carcinoid syndrome.

Your doctor might recommend this test if you have

• A previous diagnosis of carcinoid tumours,
• A family history or genetic risk factors for carcinoid tumours,
• Symptoms suggestive of other serotonin-related conditions such as depression, anxiety, and sleep disorders.

Elevated levels of 5-HIAA in urine may indicate the presence of a carcinoid tumour or other conditions that affect serotonin levels.

Here’s what you should expect during this test:

•    You will be given a special container to collect all your urine over 24 hours.

•    The sample should be kept refrigerated until it is brought to the laboratory for testing.

To prepare for this test, remember the following points:

• Consult your healthcare provider for specific directions before the test.
• Drink plenty of fluids and follow any other instructions provided by your doctor.

You might be asked to provide a CT scan, ultrasound report, and medication history to help your doctor interpret the test results

Other tests that may be ordered alongside 5-HIAA test include

• Chromogranin A Testing: This blood test measures the chromogranin A hormone and is used to help diagnose and monitor carcinoid tumours.
• Gastrin Testing: This blood test measures the hormone gastrin and helps diagnose gastrinomas – tumours that produce excess amounts of gastrin. 
• CT Scan or MRI: Imaging tests like CT scans or MRI may be used to locate and identify tumours in different parts of the body.

24-hour urine 5-hydroxyindoleacetic acid test or the 24-hour urine 5-HIAA test.

Cancer of the mid-gut or mid-gut carcinoid develops in the digestive tract, usually growing slowly in the small intestine, appendix, or colon. The tumors can be non-cancerous or cancerous and may produce too many hormones, such as 5-HIAA in your blood.