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Webinar Replay: Understanding and Interpreting Complete Blood Count (CBC) Results

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Published on March 30, 2017

Understanding your complete blood count (CBC) results and staying up-to-date on new testing methods could help provide more information about your cancer and impact your treatment decisions. Watch the replay of our virtual webinar, as Patient Power founder Andrew Schorr leads a panel of experts, including Dr. William Wierda, Dr. Susan Leclair and Lynn Ingram, in a discussion on the meanings of lab test results in easy-to-understand terms.

Sponsored by AbbVie. Produced by Patient Power in partnership with AACC's Lab Tests Online and The University of Texas MD Anderson Cancer Center. These organizations have no editorial control. Patient Power is solely responsible for program content.

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Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That's how you’ll get care that's most appropriate for you.

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

Andrew Schorr:

Hello and welcome to this Patient Power live video webinar. I’m Andrew Schorr from Philadelphia today. And you’re going to meet our guests around the country. This is to discuss helping all of us understand our blood tests, what results mean. And I should tell you we’ll have even as many as 1,100 people today, so it’s quite a crowd. And the people with different conditions, I was diagnosed with CLL, chronic lymphocytic leukemia, in 1996, and believe me I’ve been poked a lot, many many blood tests and biopsies as well. And I was diagnosed with another blood-related cancer, myelofibrosis, so I’m monitored closely—you may be too, or your loved one. And if you have one of these MPNs like myelofibrosis, polycythemia vera, some people may have myelodysplastic syndrome and CLL or maybe one of the other leukemias.

So we have a crowd that is with us. I want to introduce our guests and also tell you that you can send in questions, and we’ll get to ones we can. This the first in a series, so we’ll be doing other programs as well. If you have a question, and maybe you’ve already sent one in, send it to [email protected], [email protected] I want to mention as we talk about blood tests and blood test results, you know this can be confusing. Some people know a lot. Some people know a little. So we’ll try to get everybody up to speed. Then about your own results, that’s what you discuss with your doctor, maybe with your physician’s assistant or nurse practitioner, whoever’s part of your healthcare team to really get more perspective. Okay. Ready to go?

I want us to meet our other guests, so they are joining us around the country. We have two noted laboratory science experts, and so we also have with us a leading clinician. So you see popping up on the screen Dr. Bill Wierda. Dr. William Wierda is actually the Medical Director for the Department of Leukemia in the Division of Cancer Medicine at The University of Texas MD Anderson Cancer Center in Houston. He’s also the head of the CLL program there. Bill, thanks for being with us.

Dr. Wierda:

Thanks for having me.

Andrew Schorr:

Okay. And then we also have Susan Leclair, Dr. Susan Leclair, PhD. I want to get this title right. Susan, you’re joining us I think from Dartmouth, Massachusetts, and you’re the Chancellor Professor Emerita from University of Massachusetts Dartmouth, and of course how many years a Professor of Laboratory Science, like 40?

Dr. Leclair:

I started when I was very young. Actually, I’ve been in the field almost 47 years. So, yes, I started as a child.

Andrew Schorr:

Okay. And then Lynn Ingram is joining us from Tennessee, and we’ll see if we can get Lynn’s video popped up there. Lynn Ingram is also a laboratory science expert, and she’s a retired clinical professor in laboratory science from the University of Tennessee. She joins us from Memphis. Lynn, thanks so much for being with us. How long have you been in the field?

Lynn Ingram:

A little less than Susan but not a whole lot so about 40 years. Been around a while.

Andrew Schorr:

Okay. And I think I had known Dr. Wierda about 15 or 20 years. We’re all old friend, and, Lynn, thank you for being with us. 

So let’s start with the basics. I want to start with you, Bill, here’s my question. Why does a physician order a blood test? What do you wanna check out just as a baseline? A patient walks in the door, why do you say you need to go down to the lab? 

Dr. Wierda:

So it partly, it mostly depends on what their diagnosis is. So what the blood test gives you, there are several things to order in terms of blood tests. You can get a complete blood count, or CBC, and you can get the chemistries as well as a number of other tests. So the physical orders will depend on what the diagnosis is. So in terms of what I look for or look at, just paying particular attention to the CBC, what I’m interested in knowing depends a lot on what the diagnosis for the patient is. But the parameters that are the most important for us for most patients are white blood cell count, and that gives us how many of the white blood cells. And then the next parameter would be the differential, which tells us how many of each type blood cell is there. And then the next parameter I think that is important that we look at across the diagnoses is what the hemoglobin is and then the platelet counts. So those parameters are the most important parameters. When you get a CBC, you get a number of different results. Most of them we don’t look at. The ones that we really look at and pay attention to are, the white blood count, as I mentioned, the differential, the hemoglobin and the platelet count. The other ones we do look at occasionally, because it can be important for certain diagnoses, but for the most part those are the most important things that we pay attention to.

Andrew Schorr:

Okay. We’re going to get more into when you look at certain things, but I want to dig into some of these are that show up on blood tests. I want to mention for our audience, of course we’re tested at the outset, walk in the door. Hi, Dr. Wierda, you’re going down to the lab. Here’s the lab order. But it’s also when we are being followed, for me with CLL, it was four-and-half years before I ever had any treatment. But depending upon the diagnosis and your situation. When you’re in treatment, and I know I got blood tests all the time, when I was on FCR treatment for CLL years ago, not just because I was in a clinical trial but because they wanted to monitor me carefully. And then maybe when you complete a treatment, you’re being monitored, but maybe you’re going to need treatment again, and do you? 

So putting that in context, Susan Leclair, so Dr. Wierda mentioned a couple things. He said a couple things I don’t know if we always understand, so differential. Could you help us understand what a differential means and the different components of it and why it may be important?

Dr. Leclair:

All right, and I’ll first start by apologizing for whatever coughing and scratching you’re hearing, it’s a cold, and I can’t seem to get rid of it. So the white blood cells come in five major categories. Any one of them can be increased or decreased depending on the situation. So the logic question from Dr. Wierda to me is it’s nice that you got a white count. What kind of cells are they? Are they mature? Are they immature? Do they look functional or not? There are two ways to do a differential. The first one is an automated differential, the multi-channel instruments we have do that quite well. They count a very large number of cells, so they would be able to define cells that had granules as opposed to cells that do not, cells that have a large nucleus against those that do not. Those are the kind of characteristics that an automated differential is going to give you. Then there’s something called a traditional or manual differential, and that is a much narrower number of cells. An automated different, the machine might count a thousand, 2,000, 50,000 cells.

I’m not gonna do that. I’m gonna sit at a microscope and count anywhere between 100 and 500 more often than not 100, cells, and I’m going to be able to use whatever experience or nuance that I might have to say a little more about the quality of the cells that maybe an instrument might miss or might question. An instrument might flag something saying don’t know if it’s X or Y, and it’s back to a human to determine if it’s X or Y. So what you’ll get when you get a differential is you’ll get a count from the machine usually either ABS or a # sign after it, and that’s the machine evaluation. And then you’ll get something with a percentage sign after it, and that’s the individual or manual differential. Both give you important information.

Andrew Schorr:

Okay. Hey, I wanna go back to Bill before we get to Lynn. I have a question. So when some of us are in treatment, depending upon what our treatment is, sometimes you worry about certain kind of cells, one kind I’m thinking of are neutrophils, and our ability maybe to fight infection. I know when I went through chemo and all that, my neutrophils got low, and I was told maybe you shouldn’t shave with a regular razor and stuff. So that’s an example of something, Bill, that comes out of the neutrophils that you’re watching related to a red flag perhaps?

Dr. Wierda:

Right. So when patients on chemotherapy particularly, the chemotherapy is toxic to the leukemia that’s in the bone marrow but also to the normal cells. So one of the things that we have to monitor are the blood counts and the differential and the percent of neutrophils, ‘cause we don’t want to give too much chemotherapy, and we don’t want to give it too soon the next cycle too soon, because you can compound the toxicity. So in your example for sure what we do monitor is the neutrophil count and making sure that it doesn’t go too low and that it recovers in a timely fashion so that the patients are ready and able to go onto the next cycle of treatment. So neutrophils we pay very close attention to, also the same holds true for platelets.

Andrew Schorr:

And platelets, Lynn, my platelets are monitored with an MPN, the the fact that the medicine i have too is monitored for platelets, and I’ll share about 75,000. One time they got to 55,000, and I can bruise or worry if I have a nosebleed or cut shaving. Platelets are the stickiness in blood, right Lynn?

Lynn Ingram:

Sue may be able to answer that a little better than me. I’m the chemist in the group, so she’s gonna do the imagology phase.

Andrew Schorr:

Okay. So let’s go back to you, Susan. But platelets, and, of course, besides whether the platelets are good platelets, but platelets are supposed to help us coagulate and things like that.

Dr. Leclair:

Right. So think of platelets as the cotton gauze that you use when you are putting your hand up against a cut. They form a web. They interact like this. I gotta do this (interlacing hands). It’s the teacher in me. They interact like this. They form an interlocking web that causes the damaged area to be pulled together so that less blood is being lost, less blood cells getting through that web of interconnection and allows for clotting to happen effectively and efficiently. So assuming that they’re good, and quality is a different thing than quantity, assuming that your platelets are good, what you want them to do is recognize that there’s someplace that’s damaged, come form a mat over it and allow blood clotting to occur.

Andrew Schorr:

Okay. So when somebody is bruising, Bill, maybe they either don’t have enough platelets, or their platelets aren’t top quality, right?

Dr. Wierda:

Correct. Or they’re on a drug that affects the platelet function, so the platelets aren’t working as well or effectively, because the drug is suppressing that function. 

Andrew Schorr:

Okay. Now I’m gonna go to Lynn. Lynn, we have some patients with us who have multiple myeloma. And there are terms that come for us sometimes in myeloma, light chain and all kinds of things like that. What tests are done to help understand somebody’s myeloma situation?

Lynn Ingram:

Well, there are a few things that you can do to get some good information about what exactly is going on. But a little backup here on where the heavy chains come from, the plasma cells, which are the problem in myeloma, make antibodies, and antibodies are made up of four different protein chains. Two of them are short chains, and they are called the light chains. And two of them are long chains, and they are the heavy chains. And it depends on exactly which plasma cell has gone kinda nuts and is malignant and making many many copies of those proteins. And so they are found in the blood. Some of them can be found in the urine. And we will actually do tests to see not only how many of those light chains that that abnormal plasma cell is making, what type is it? Is it a kappa cell or a lambda type? One of the two. And so it helps again to identify exactly what’s going on and exactly which abnormal proteins those plasma cells are producing.

Andrew Schorr:

Okay. Now, Susan, I’m willing to bet that most the people on this program when they’re given their blood test results back, and I would say always ask for them. We’re gonna have depending on the lab reports, I know that H’s and L’s, all over the place. And it says the normal range, and I’m high, I’m low, this and that. It’s kind of unnerving, but some of us have been living with this for a long time. So what do those ranges mean, and how are those ranges established?

Dr. Leclair:

For every single test in every single laboratory, the laboratory staff must create a reference range, a range against which their physicians can compare their individual patient’s results to a population. That means very rarely are you ever going to get exactly the same reference ranges between two or three or five facilities that causes trouble with people sometimes. But what we typically do. We want these ranges to describe the typically healthy person. So if I’m going to be doing a test for hematocrits, I want a population of adult men, because that will reflect a certain kind of range, a population of healthy adult females, maybe children or whoever else is in my local area that’s gonna be using my instrument. And the math that I use for them will describe that 95 percent of all of the healthy people I tested fall within this number and this number. And that’s what’s defined as a reference interval or a reference range. It’s a thumbnail handy thing to give to a physician. And the instruments, because they are computers, very dutifully will look at a 10.1 and say that’s 0.1 higher than 10, it must be an H, or it must be an L. I think physicians like H’s and L’s in some circumstances, but I suspect they are the bane of their existence in others, because H’s and L’s only mean that you have fallen in or out of what my reference range is. It doesn’t mean that it’s unhealthy or healthy for you. That’s Bill’s job. What has to happen is I have to send this stuff to him, and he’s the one who takes the number range, the H and the L if there is one, who you are, what you are, are you 17? Are you 79? Are you recently conquered Mount Everest, or was the most important thing you ever done was change your channel with your remote? He’s the one who has to take all of that into consideration and make sense as to whether that H or that L is meaningful. So I’m going to turn the rest of this over to Bill to try and figure out. Do you actually even look at H’s and L’s?

Andrew Schorr:

Yeah. Well, he’s shaking his head.

Dr. Wierda:

No, I actually don’t usually look at H’s and L’s, because I know the values that I expect, and I have in my own mind what the reference range is for a particular patient for a particular diagnosis. So I pay less attention to the H’s and L’s. And sometimes an H or an L is okay for patients for a particular patient. So, for example, if we’re talking about a low hemoglobin, the hemoglobin may be slightly below the normal range, but that’s okay for CLL, in most situations. What we really pay attention to or what I pay attention to is the hemoglobin dropping, is it less than 10 or 11? And that’s when I need to make a decision or have a discussion about treatment or what have you. So I have in my own mind what the reference ranges are for a particular patients and diagnosis.

Andrew Schorr:

One of the factors that’s called for those of us with an MPN is LDH, and one of you ladies can tell us what that means. But mine has been high for years, and I see and say, yeah, so what? Typically my myelofibrosis doctors say, well, that’s what we expect, because you have myelofibrosis. Susan, what is LDH? I’m just going to get you to define some terms for us real quick.

Dr. Leclair:

Okay. Well, it’s my turn to hit the ball back to Lynn, because that’s a thing.

Andrew Schorr:

What’s an LDH thing?

Lynn Ingram:

LDH, or LD, you’ll see in both forms, is lactic dehydrogenase. It’s an enzyme that’s found in just about every cell in your body, because it helps you to use glucose for energy. So it’s kind of a big picture number. When you get an LD, it tells you how many cells are leaking this enzyme out of the inside of the cells and now is in the bloodstream. So it can give you an overall of how healthy the cells are, how damaged or how diseased they’d be. It’s a real good way to kind of monitor overall the big picture of kind of every cell in your body, and I think you hit it right when you said high LDs in certain instances are just a comfirmation of the process that’s going on. The concern is is it getting higher and higher and higher and higher? Or is it staying about the same? And then you know that you’ve got a stable level.

Andrew Schorr:

Right. Okay. So, Bill, when I go to my doctor now in San Diego, we look at the chart of the trend, and, thank God, most of my trends have been pretty level. So is that what’s the reason or successive tests is first, where are you now? Where have you been? Let’s see how you are over time. And do you look at that more than the H’s and the L’s?

Dr. Wierda:

So, correct, particularly for the chronic leukemias. So for the chronic leukemias, things change relatively slowly as opposed to the acute leukemias. And so it’s very important to monitor the trends in terms of how the white count’s changing, for example, or how the hemoglobin’s changing and with what pace those changes are occurring. Now, I often have discussions about this with patients when they come in and say, oh my gosh, my last white count was much higher than I expected or was lower than expected. What does that mean? And so my response in always, I don’t usually pay attention to one number, particularly for CLL, because the numbers can vary from time to time or from test to test. And what’s most important for CLL is what the trend is and repeating the tests in a couple months for situations where the numbers are much different than you expected, like the white count is unexpectedly high, and you really want to know that’s a real number. I will usually confirm that with a repeat test in a couple months. So I tell people, things with the chronic leukemias things happen relatively slowly. I never get excited about a single test result, and everything needs to be repeated or confirmed if there are things that are unexpectedly different.

Andrew Schorr:

I have one other question for you. So you’re at a major center at MD Anderson. So people come to you from all over the world. And Susan was talking about computerized testing. So when I walked into MD Anderson even though I’d had a lot of testing in Seattle where I used to live, you guys did a whole bunch of testing again. So how much confidence do you when you have people you see from somewhere else that the results they bring in are—you just go with that? How often do you want to do your own? Do you have any concern about differences between labs, things like that?

 

Dr. Wierda:

So it sort of depends on the diagnosis. For example, for CLL, it’s unusual for us to have patients who come in as new patients and have the diagnosis changed based on the workup that we do. We do like to if it’s been a while since the last test was done, we do like to repeat those. So, for example, if it’s been a couple years since the FISH was done for CLL and it’s time to start treatment, then for sure we would repeat the FISH test. For other of the diagnoses that we deal with in leukemia, we can see changes in the diagnosis in about 20 to 30 percent of the time. And I think that comes from the expertise of the people who are reviewing the material here, because they see a lot of it.

Andrew Schorr:

Like our ladies who are experts at it right, the hematologists.

Dr. Wierda:

Exactly. So we do see changes in the diagnosis. So for sure for the acute leukemias, we redo all of the diagnostic workup when they come here as new patients if it’s an untreated patient as well as previously treated patient. But, again, the repeat testing will really depend on the diagnosis. 

Andrew Schorr:

Okay. We’re gonna skip around a little bit. Which one of the ladies wants to go fishing with us? What is a FISH test? What does it mean? Lynn, are you up on that?

Lynn Ingram:

That goes back to Sue.

Dr. Leclair:

Gee, thanks. A fishing test is almost exactly that. It really means fluorescence in situ hybridization. Now having spelled it, let me take a chemical that I know is going to flash in the dark. I’m going to attach that to an antibody. That antibody, or maybe it’s not exactly an antibody, maybe it’s a short chemical sequence of some sort is going to connect with or bind to a piece of the cell membrane or a piece of the DNA of the patient’s cells. And once bound to that piece of cell or DNA causes that cell to flash, to make light. And I can identify cells that well, glow in the dark and cells that don’t. And I can determine to a greater or lesser extent, you got a lot of these, you don’t have too many of these. I can in some instances count them and give you a quantification. Or in other instances where the number is not as critically important, I can give an answer that says, yes, they’re there - no they’re not. 

For example, I know there are probably people listening who have got polycythemia vera. There’s one particular genetic mutation that is found in 95 percent or more of people with p. vera. I can go hunting for that one mutation, and I can say to Dr. Wierda, your patient’s got it, or they don’t. So it doesn’t have to be a number. It can sometimes just be a yes or a no. The problem with FISH is if I’m looking for the one problem that I see in disease number one, I may not see something that might be associated with disease number two or three. So I give you a highly sensitive, very-focused answer. That’s what FISH does.

Andrew Schorr:

Okay. Now, I don’t know who wants to explain this. But I know for those of us with CLL, and there are many watching, what we’ve learned over the years, and I’ve lived with it for a long time, are sub-types, chromosomal sub-types, right? And there are medicines that are now approved for different sub-types, so what test figures that out? Who wants to explain that? Sue?

 

Dr. Leclair:

Yeah. Sure, I’ll take a chance. Yes, sometimes the FISH test will do that. Other times, there will be a test called the PCR, which thanks to another Nobel Prize, is polymerase chain reaction, where I can look for a very small piece of DNA. They’re very small, and I can cause the sensitivity of my test to increase, so I can get just that. There are two different kinds of testing there. We even have the third one, which I think everyone has mentioned, and I’ll put it into completeness, which is FLOW cytometry. You pick up whether or not there’s a marker or a chemical or a structure that’s on the cell. If I can take that structure, let’s say it’s a hook-shaped structure like this and it’s sticking out from the top of the cell, I identify that you have this hook-shaped structure. It is possible for a pharmaceutical company to make something that knocks that structure off or binds to it in some way, making that cell less effective where it will maybe die sooner or work less.

Andrew Schorr:

Well, we have an example. Wasn’t it a notable example of a drug kind of helping, I guess we’re talking about a chromosomal abnormality? Bill, isn’t that where imatinib (Gleevec) came in?

Dr. Leclair:

That’s right.

Andrew Schorr:

The so-called Philadelphia chromosome, what CML patients, most have, right?

Dr. Wierda: 

Correct. So that is an example of targeted therapy, and I think what you’re getting at is where we’re moving with therapies for leukemia, and that is more of a personalized therapeutic approach where we fully characterize a patient’s particular disease and can identify chromosomal abnormalities or mutated genes or expressed proteins. And that helps us to direct the most appropriate and effective therapy.

Andrew Schorr:

Okay. Now let’s go on to proteins. Who wants to talk about proteins? I know when I received rituximab (Rituxan) as part of my treatment, people get obinutuzumab (Gazyva) or ofatumumab (Arzerra) and some of these others, it’s targeting a protein for the surface of the cells. Who wants to explain that? One of you ladies?

Dr. Leclair:

We’re back to the hook.There is a protein called CD20 that is found on lymphocytes, particularly B lymphocytes, not all of them. And not all B lymphocytes either. But if you’ve got that hook, then it is possible to build an antibody against that CD20. And as long as the cell is willing to make CD20—and some of them unfortunately learn that they don’t really have to live it, they can live without it—this rituximab, this antibody, MAB means antibody, this antibody comes along, grabs ahold of that CD20 structure and causes that cell to be damaged minimally or to die. Sometimes alone by itself or sometimes with other drugs, so as long as that works that’s almost the holy grail if you have one damaged protein, a CD20, and I give you an anti-CD20, and your signs and symptoms go away. Is it the holy grail of a single drug? Maybe not, but it’s much further along than we’ve done before, and this whole all the ads that all end up with incomprehensible words ending with MAB, this is all due to this thought of find something that’s unusual about that cell and go after it.

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

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