How the Test is Performed

The test depends on what type of sample is needed.

• For a urine sample, see urine collection -- clean catch or urine collection (infants).
• For a blood sample, see venipuncture.
• For a cerebrospinal fluid sample, see CSF collection.

The sample is sent to a lab, where it is mixed with latex beads coated with a specific antibody or antigen. If the suspected substance is present, the latex beads will clump together (agglutinate).

For example, if your health care provider suspects that your child has strep throat, a throat swab is taken. The sample is mixed with latex beads that are coated with antibodies against the bacteria. If your child has strep throat, the bacteria in the sample will react with the antibodies on the latex particles, causing clumping.

Latex agglutination results take about 15 minutes to an hour.

How to Prepare for the Test

Your health care provider may tell you to limit certain foods or medications shortly before the test to ensure accurate test results.

Why the Test is Performed

This test is a quick way to determine the absence or presence of an antigen or antibody. Your health care provider will base any treatment decisions, at least in part, on the results of this test.

Normal Results

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

If there is an antigen-antibody match, agglutination will occur.

Updated: 4/16/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.