String test

• Illustrations
• Alternative names
• Definition
• How the test is performed
• How to prepare for the test

• How the test will feel
• Why the test is performed
• Normal Values
• What abnormal results mean
• Special considerations

Alternative names    Return to top

Definition    Return to top

This test involves swallowing a string to obtain a sample, which is then tested to detect the presence of intestinal parasites. The string test is rarely performed in the U.S.

How the test is performed    Return to top

You swallow a string with a weighted gelatin capsule on the end and then it is pulled back out after 4 hours. Any bile, blood, or mucus attached to the string is examined under the microscope for cell types and segments of parasites or eggs.

How to prepare for the test    Return to top

Food and fluid may be restricted for 12 hours before the test.

For infants and children:

The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

How the test will feel    Return to top

You may find it difficult to swallow the string, and you may feel an urge to vomit when the string is pulled up.

Why the test is performed    Return to top

The test is performed when there is a suspicion of parasitic infestation but parasites are not detected by stool examination.

Normal Values    Return to top

No presence of blood, parasites, fungus, abnormal cells, or bile is normal.

What abnormal results mean    Return to top

Abnormal results may indicate the presence of giardia or another parasitic infestation.

Special considerations    Return to top

Previous drug therapy can affect the test results.