Gettysburg Medical News
The Clinical View
by P.E. Hoffsten, MD
23 April 2008

HOW DO WE USE A COMPLETE BLOOD COUNT?

            A lady recently came to the clinic with a complaint of fatigue, lack of energy, just not feeling herself and just knew that something was wrong.  Initial evaluation included her recent history; that was really uneventful except for the fatigue syndrome.  Physical examination showed her to be somewhat pale, but otherwise unremarkable.  There was no history of bleeding and her diet had apparently been unchanged and normal.

            Unfortunately, she had no source of medical insurance and whatever tests or treatments were to be done would be at her personal expense.  She made it clear that her finances were limited and she didn’t want a series of unnecessary tests.  I told her that she appeared to be somewhat pale indicating anemia and a complete blood count would be an appropriate starting point.  When that test was done, it showed that she had an iron deficiency anemia.  At that point, she volunteered that she had similar diagnoses in the past and wondered why the anemia was still present since she was taking iron pills.  Her stools had been checked and there was no blood hidden in her stools.  She was post menopausal and was no longer having bleeding on a monthly basis.  Thus, there was not an obvious blood loss.  In a post menopausal female, the most common reason for iron deficiency anemia is bleeding someplace but she really no history that would reveal a source of same. 

            It was at this point, that she asked to see the complete blood count sheet and wanted an explanation of what the various components meant and how I could be so sure that she had an iron deficiency anemia.  So we started down the list of what each entry represented.  The first item was a white blood cell count.  A normal value is 5,000 to 10,000 white cells per cubic milliliter which is a little tiny unit of volume.  When values are below 5,000, it usually means that the bone marrow isn’t making enough white cells and there may be something wrong such as bone marrow failure.  When the white cell count is greater than 10,000 cells per cubic milliliter, the patient is making many more white blood cells than normal.  This could mean an infection or it could mean something as ugly as leukemia. 

            I pointed out to her that her white blood cell count was normal.  Further down the list of things that were measured in the complete blood count were the so called “differential white count”.  This is a measure of the different kinds of white cells in the person’s blood.  There are white cells called “polys”.  These are cells that deal with infection.  When they are very high, it would be a suggestion that she has an infection someplace but her value was normal.  Another type of white blood cell is called a lymphocyte.  These are white blood cells that are involved in immunity and protecting against infection.  Too many lymphocytes can mean a leukemia but her value was normal.  A third type of white blood cell is called a monocyte and it is involved in certain types of fungal and viral infections.  Her value was normal here also.

            Lastly, there are two kinds of white blood cells that have to do with allergy.  One of these is called an eosinophil and the other is called a basophil.  Eosinophil counts being too high or basophil counts being too high usually means that a person has an allergy to something but hers again were normal. 

            I then explained to her that there were two measures of anemia.  One of these is called  hemoglobin which is the amount of oxygen carrying protein in the blood and the other is called the hematocrit which is the volume of the cells that carry hemoglobin.  The machines that do complete blood counts now can measure the size of the red blood cells, the distribution of the different sizes of red cells and the amount of hemoglobin that is contained within the red cells.  This is very valuable information and can identify the cause of the person’s anemia.

            I pointed out to her that her red blood cells were abnormally small and that the distribution of the different sizes of the red blood cells was also abnormal.  These two findings together made the diagnosis of iron deficiency highly likely.  Alternatively, her red blood cells might have been too big.  This type of anemia occurs in people that have Vitamin B12 deficiency or folate deficiency or those that are making new red blood cells very quickly.  It also happens in a relatively rare condition called hereditary spherocytosis in which the person’s spleen breaks up their own red blood cells too quickly.

            Lastly, the complete blood count contains a count of the number of platelets that the person has.  Platelets are those tiny fragments of blood clotting material that are always in the blood to protect against bleeding.  Rarely, the platelet count can be too high and cause clots that are inappropriate.  Alternatively a platelet count can be too low and the person can have bleeding problems. 

            With the above explanation, the patient was told that she had an iron deficiency anemia based upon her blood count.  In addition, based upon the absence of hidden blood in her stool and the absence of menstrual bleeding, the most likely cause of her problem was that her stomach just didn’t absorb iron in a normal manner.  About 10% of the population has this problem.  Very frequently, simply taking an iron pill with 500 mg a day of Vitamin C will facilitate absorption of iron and correct the problem. 

            In this particular lady, that was the therapeutic step that was taken and when she returned a month later, her blood count had returned quite substantially and her problem was easily solved based upon a simple complete blood count.

            Some individuals are not quite as fortunate as she was.  They do not absorb iron even with the Vitamin C and they have to have iron injected on a periodic basis.  This can be done with a single intravenous administration or alternatively in a cheaper basis it can be done with weekly iron injections for six or eight weeks to replenish the person’s iron.

            Other situations in which complete blood count can be very helpful in making a diagnosis include pernicious anemia in which the person is vitamin B12 deficient.  Now that diagnosis can easily be made from a complete blood count and can be easily corrected with a small lozenge that the person takes daily to allow vitamin B12 to enter their body. 

            In summary, complete blood counts are very valuable for monitoring the side effects that come from chemotherapy for malignancies, for following a person’s blood counts in chronic renal failure, or monitoring people that have a propensity to bleeding or patients with leukemias or platelet disorders.  Sometimes, as in this lady, it is all that is needed along with a history and physical exam to solve the problem of her chronic fatigue.

This and other columns available at www.macpierre.com.