The NET Alliance™ and Novartis Oncology continue their commitment to improving knowledge and management of neuroendocrine tumors, and empowering patients to be more informed advocates.

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Talk to your doctor about which tests are right for you. Your doctor can help you better understand the tests and any risks that may be associated with them. Your doctor can also tell you how long it will take to receive your test results.
Keep detailed notes of tests you’ve had and your results. Be sure to ask your doctor about your test results and what they mean. If you have a test more than once and the results change, ask your doctor what this means. It’s important for you to understand why your doctor is ordering certain tests and what your results mean. Keep notes of your doctor’s answers, too.

Tests for GI NET (carcinoid): What are they and why should you have them done?

Your doctor may order a number of tests to learn about your carcinoid or gastrointestinal neuroendocrine tumor, known as a GI NET.

Some tests help your doctor find your neuroendocrine tumor. Other tests help your doctor track changes in your neuroendocrine tumor over time.

Imaging tests

Imaging tests use special machines to look at your organs or tissues. These tests may help with neuroendocrine tumor diagnosis or to see if the tumor is growing or has changed.

Click on a test below to learn about the test and how it’s done.

CT Scan

A CT scan shows the location and size of your tumor.

Having scans over time will tell your doctor if your tumor has grown, changed, or spread.

How it’s done

If your doctor orders your test with “contrast,” you will either drink a fluid or receive an intravenous (IV) injection before the test. Contrast helps certain areas show up in the images.

A CT scanner is shaped like a large doughnut standing on its side. You will lie on a table that slides you into the doughnut hole while the scanner takes pictures.

The table may move slightly. You may also hear clicking or whirring noises.

You may need to hold your breath to make sure the pictures are clear.

MRI Scan

An MRI scan shows the difference between healthy tissue and a tumor.

Having scans over time will tell your doctor if your tumor has grown, changed, or spread.

How it’s done

If your doctor orders your test with “contrast,” you will get an intravenous (IV) injection before the test. Contrast helps certain areas show up better in the images.

During the test, you will lie on a table while the machine takes pictures. It may make tapping or thumping noises.

You need to stay very still to make sure the images are clear.

Octreoscan

An Octreoscan* may help find a tumor that may not have been seen by other tests.

Having scans over time will tell your doctor if your tumor has spread.

How it’s done

Before the test, you will get an injection to place a special “tracer” into your body. The tracer helps certain areas show up better in the images.

You will lie on your back during the scan while the machine takes pictures. You can breathe normally.

You need to stay still to help make sure the images are clear.

*Octreoscan is a trademark of Covidien AG or one of its affiliates.

Biochemical tests

Biochemical tests measure the levels of certain substances in your blood or urine. Your doctor may order biochemical tests to help determine whether or not you actually have a NET or to measure the amount of certain hormones.

Click on a test below to learn about the test and how it’s done.

Chromogranin A (CgA)

A CgA test measures levels of CgA in your blood.

CgA is a substance released by most types of NET.

Your doctor may order a CgA test to help determine whether or not you actually have a NET.

You may continue to have this test so your doctor can measure your CgA levels over time.

How it’s done

A needle is inserted into your arm to take a sample of blood.

The sample is sent to a lab to be tested.

Hydroxyindoleacetic acid test (5-HIAA)

A 5-HIAA test is a 24-hour urine test.

Your doctor may order a 5-HIAA test alone to measure how much of the hormone serotonin is in your blood. Serotonin is a hormone made by certain cells in the body, mostly in the GI tract (digestive system). Serotonin helps with various functions, such as digestion.

Your doctor may order this test more than once to help watch for a neuroendocrine tumor that may cause carcinoid syndrome.

How it’s done

You will urinate into a special container over a 24-hour period.

After 24 hours, you will return the container to be tested.

Please note that some types of foods and medicines can increase the 5-HIAA in your urine. This could result in incorrect results. Ask your doctor for a complete list of foods and medicines that you should avoid before a 5-HIAA test. Here are some examples

  • Bananas
  • Avocados
  • Plums
  • Eggplants
  • Tomatoes
  • Plantains
  • Pineapples
  • Walnuts

And medicines with

  • Guaifenesin (found in cough medicine)
  • Acetaminophen (Tylenol®)
  • Salicylates (found in aspirin)
  • L-dopa (found in Parkinson’s disease medicine)
  • Proton-pump inhibitors (antacids) 

Tylenol is a registered trademark of McNeil Consumer Healthcare.

Get involved 

Talk to your doctor about which tests are right for you. Your doctor can help you better understand the tests and any risks that may be associated with them. Your doctor can also tell you how long it will take to receive your test results.
Keep detailed notes of tests you’ve had and your results. Be sure to ask your doctor about your test results and what they mean. If you have a test more than once and the results change, ask your doctor what this means. It’s important for you to understand why your doctor is ordering certain tests and what your results mean. Keep notes of your doctor’s answers, too.