Name of the Procedure:

5-Hydroxyindoleacetic acid (5-HIAA) Test

Summary

The 5-Hydroxyindoleacetic acid (5-HIAA) test is a diagnostic urine test used to measure the level of 5-HIAA, a metabolite of serotonin. This test is often used to help diagnose certain types of tumors, known as carcinoid tumors, which can secrete serotonin.

Purpose

The primary goal of the 5-HIAA test is to detect abnormal levels of 5-HIAA to aid in the diagnosis of carcinoid tumors. By identifying elevated levels, it can indicate the presence of these tumors, which can then be further investigated and treated.

Indications

• Persistent flushing of the skin
• Diarrhea
• Wheezing
• Heart palpitations
• Unexplained weight loss
• Known carcinoid syndrome symptoms

Preparation

• Patients may need to avoid certain foods such as bananas, avocados, tomatoes, plums, eggplants, and walnuts for 3 days before the test as these can affect serotonin levels.
• Certain medications might need to be stopped prior to the test. Always consult your doctor before stopping any medication.
• A 24-hour urine collection is required for this test, so the patient should be given a special container to collect all urine over a 24-hour period.

Procedure Description

1. Collecting the Sample:
   • The patient will be provided with a container for a 24-hour urine collection.
   • The first urine of the day is discarded, but all subsequent urine is collected for the next 24 hours, including the first urine of the next morning.
2. Storing the Sample:
   • All collected urine should be stored in the provided container and kept cool, usually refrigerated.

3. Submitting the Sample:

   • After the collection period, the patient brings the sample to the lab for analysis.

   There are no tools, anesthesia, or sedation required for this procedure.

Duration

The urine collection takes 24 hours, but the actual handing over of the sample to the lab takes only a few minutes.

Setting

Urine collection is performed at home. The sample is then brought to a laboratory for analysis.

Personnel

Lab technicians will analyze the urine sample. The ordering and interpretation of the test will be conducted by your healthcare provider.

Risks and Complications

• The test is non-invasive and has minimal risk.
• If the instructions for collection and storage are not followed correctly, it can lead to inaccurate results.

Benefits

• Helps in the accurate diagnosis of carcinoid tumors.
• Allows for early intervention and treatment.
• Non-invasive and straightforward.

Recovery

• No recovery time is needed as the procedure is non-invasive.
• No specific post-procedure care is required.

Alternatives

• Blood test for serotonin levels.

• Imaging studies such as CT scans, MRI, or Octreoscan for locating carcinoid tumors.

  Each alternative has its pros and cons. For example, blood tests might not be as reliable if the tumor secretes serotonin intermittently, and imaging studies might be more expensive or involve exposure to radiation.

Patient Experience

• The patient will collect urine over a 24-hour period and may need to keep the container refrigerated.
• The process is straightforward and non-invasive, with minimal discomfort.