Immunostaining is a process healthcare providers use to diagnose infections, cancers and other conditions. It identifies a specific protein (like a cancer-causing protein) from a mixture of other proteins in a sample of your blood or tissue.


What is immunostaining?

Immunostaining is a process pathologists use to diagnose certain diseases, such as infections or cancer. The purpose of immunostaining is to identify a specific protein molecule from a mixture of other proteins in a sample of your blood, bone marrow or tissue.


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Test Details

How does immunostaining work?

Immunostaining uses antibodies to identify and specifically label antigens that providers are looking for. It’s like using a highlighter to call out important lines of text.

The staining of immunostaining isn’t quite like tie-dying a shirt. Staining techniques use special dyes, color-changing enzymes, fluorescent molecules and even gold particles to label proteins and cells so researchers can see them.

Before the immunostaining process can begin, a healthcare provider must take a sample of your blood, bone marrow or tissue. Then, they’ll send it to a pathologist for testing. While providers obtain blood and tissue samples at a hospital or healthcare office, immunostaining always takes place in a laboratory.

What are the types of immunostaining?

Healthcare providers use several techniques, and each technique uses a different immunostaining protocol. Immunostaining methods may include:

  • Immunohistochemistry.
  • Flow cytometry.
  • Immuno-electron microscopy (EM immunolabeling).


This is the most common immunostaining technique. Immunohistochemistry involves placing a small sample on a glass slide together with an antibody that will bind to the intended target, then staining it with dyes or enzymes (immunostains). This allows a pathologist to see certain proteins and cells more clearly under a microscope.


  • Aids in the diagnosis of various types of cancer.
  • Helps with the classification of many neurological conditions and blood disorders.
  • Allows healthcare providers to study the expressions (effects) of particular genes.

Flow cytometry

With flow cytometry, a technician uses antibodies with colored labels to mark proteins they’re looking for. A laser counts, sorts and categorizes your cells one by one, like groceries through a scanner.

Healthcare providers use flow cytometry to diagnose:

Immuno-electron microscopy (EM immunolabeling)

Immuno-electron microscopy allows a pathologist to view your sample with greater magnification and in great detail. Pathologists attach colloidal gold particles to the antibodies. Colloidal gold is very easy to see under an electron microscope. So, when the antibody “grabs on” to the antigen, the pathologist can easily see it because the gold shows up as dark flecks.

In addition to detecting a wide range of viral infections and diseases, immune-electron microscopy can locate viral antigens in vaccines.


How should I prepare for immunostaining?

Usually, you don’t need to prepare for immunostaining. But your healthcare provider will give you instructions before your appointment so you know what to expect when they collect your blood, tissue or bone marrow sample.

How long does immunostaining take?

It depends on the type of immunostaining your provider uses. Some methods only take a few hours. Others may take up to 10 days. Your provider can tell you what to expect in your situation.


Results and Follow-Up

What type of results will I get and what do the results mean?

A pathologist will analyze your results and send them to your healthcare provider. The kind of results you get will vary depending on what type of test the pathologist used. Your provider will go over your test results in detail and tell you what they mean for your specific situation.

When should I know the results of the test?

It depends on which type of testing the pathologist performs. Some immunostaining methods take less than a day. Others can take up to a week or longer. When you go in to give your blood, bone marrow or tissue sample, your provider will let you know when you can expect your results.

If the results are abnormal, what are the next steps?

If a pathologist finds evidence of disease, your healthcare provider will explain the results to you and discuss your treatment options. In some cases, they’ll assemble a team of physicians to determine an appropriate treatment plan.

A note from Cleveland Clinic

Immunostaining refers to a variety of laboratory testing methods that use antibodies to identify and label antigens. Immunostaining helps diagnose a wide range of health conditions, from viral and bacterial infections to specific types of cancer. If you need immunostaining, your healthcare provider can help you understand the results, explain what they mean for your situation and whether you need treatment.


Medically Reviewed

Last reviewed on 06/19/2023.

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