Do you have cancer cells in your blood? What does the immunophenotyping test detect?

Did your doctor look at your Complete Blood Count (CBC) and say that your white blood cell count is a little high or looks abnormal? And then he or she talked about a test with a strange name called `Immunophenotyping`? When you heard that name, you probably felt a little scared, wondering what kind of test this is. It's a very common thing. So today, let's talk about this test called `Immunophenotyping` in a very simple way, in a way that you can understand.

What is immunophenotyping simply?

Simply put, `Immunophenotyping` is a specialized lab test that looks at the cells in our body, especially white blood cells, to see if they are cancerous or not. This is especially helpful in diagnosing blood-related cancers such as leukemia and lymphoma.

In this test, a pathologist, a doctor who specializes in tissues and cells, looks for specific proteins called ``antigens'' on the surface of your white blood cells. The presence of these ``antigens'', and the type of ``antigens'' present, can help determine whether the cell in question is healthy or cancerous.

If we look at the meaning of the word `Immunophenotyping`, we can explain this further:

• Immuno: This means something related to our immune system . In this test, the proteins called ``Antigens'' that I mentioned earlier are used to identify another type of protein called ``Antibodies'' that is also in our immune system. This is like a key and a lock. Only a specific key (Antibody) made for it fits a specific lock (Antigen).

• Phenotype: This refers to the outward, observable characteristics of something. So when that key (Antibody) is attached to the lock (Antigen), we can see it in a certain way. When the pathologist sees that, he knows that the relevant lock, that is, the relevant `(Antigen)`, is on that cell.

These `(Antigens)` (locks) found in cancer cells are different from those found in healthy cells. So by identifying exactly these `(Antigens)` types, this test helps to identify with certainty whether this is a cancer cell, and if so, what type of cancer it is.

When should this test be done?

Your doctor will often recommend this test if your complete blood count (CBC) shows an abnormally high white blood cell count. This can be a sign of some blood cancers. So, the ``Immunophenotyping`` test helps confirm that suspicion.

This method is also very important in cancer research. This technology is also used to study how cancer cells with certain ``Antigens`` respond to various anti-cancer drugs, especially ``Immunotherapy`` treatments.

How is the test done? What happens inside the lab?

In this test, you only have to do a very small thing. That is to provide the sample required for the test. After that, everything else happens inside the lab. You don't have to worry about it. Usually, two main techniques are used to perform this test.

1. Flow Cytometry

2. Immunohistochemistry (IHC)

Let's see what happens in these two methods.

Flow Cytometry Method

This is the most commonly used method. This method allows a large number of cells taken from blood or tissue to be tested at once. Here's what happens inside the lab:

• Taking the sample: This is usually done by taking a small sample of your bone marrow (a bone marrow biopsy). Or, more commonly, by taking a small amount of blood. Sometimes, a sample of spinal fluid or abdominal fluid may also be taken.
• Preserving the sample: In the lab, the sample is prepared by adding special chemicals to keep the cells intact and not die.
• Adding Antibody: Then comes the most important part. They add an ``Antibody'' (key) that is designed to match the ``Antigen'' we are looking for to this sample. But there is something special about this ``Antibody''. It has a small compound that emits light, a ``Fluorescent Compound'' attached to it. So when that key connects to the lock, that cell starts emitting light.
• Insertion into the Flow Cytometer: This prepared sample is then inserted into a special machine called a ``Flow Cytometer.`` As the cells move through this machine one by one, the sensors ``Detectors`` in the machine detect and count the cells that emit bright light.

With this method, it is possible to very accurately determine how many cells contain the relevant `(Antigen)`.

Immunohistochemistry (IHC) method

This method is usually used to find the `(Antigens)` present in a specific tissue sample `(Tissue Sample). Here, something similar to `(Flow Cytometry)` happens. But the biggest difference is that here, the `(Antibody)` is not attached to a fluorescent compound. Instead, an enzyme `(Enzyme)` is attached.

Because of this enzyme, when the `(Antibody)` binds to the relevant `(Antigen)`, that cell turns a specific color. Then, when the pathologist looks at it through a microscope, he can clearly see those colored cells. That way, he can confirm that the relevant `(Antigen)` is present in that tissue.

Are there any limitations or shortcomings to this test?

Yes, like all tests, this one has its limitations. The biggest challenge is that not every lab that performs this test follows the same standard methodology. This means that there can be slight variations in results from one lab to another.

What kind of things come out in the report? What does it say?

The report of an `Immunophenotyping` test is not as simple as a regular blood report. It contains data and graphs obtained from the `(Flow Cytometer)` machine. Only a trained pathologist can understand these. He analyzes that data and prepares the final report.

From that report, your doctor will receive information like this:

• What type of white blood cell is in the sample?
• What stage of development are those cells in?
• How many cells contain the tested `(Antigen)`?

The pathologist compares the data from your sample with data from a healthy person, as well as with data patterns from people with a specific type of leukemia or lymphoma. Based on this comparison, along with the results of other tests, he or she makes a conclusion about the likelihood that you have the cancer he or she suspects.

When should I talk to the doctor?

Waiting for test results can be stressful. You have a thousand questions on your mind. It's normal to feel uncertain about when the results will come and what they will say.

Maybe you're not having any problems, maybe you're surprised to see the `CBC` report. Maybe you've been feeling a little tired and unwell for a while. However, this is a time to be patient. This is just one step on the journey to finding out what's going on inside your body.

Your doctor is your best guide at this time.

• If you are not sure when you will get the results, ask your doctor.
• After you get your results, if you're not clear about what's in them, ask questions until you understand. That's your right.
• Don't get confused by what's in the report. It's the doctor's responsibility to explain what it means to you.

Your cells contain a lot of information about your health. Immunophenotyping is just one tool that can help you uncover that information and gain a deeper understanding of your health. It's normal to feel scared and anxious at a time like this. If you need support, talk to your doctor about it.

Immunophenotyping, Cancer Testing, Leukemia, Lymphoma, Flow Cytometry, Blood Cancer, White Blood Cells