Complete Blood Count

A Complete Blood Count test CBC is a diagnostic test to measure the following in blood - the number of red blood cells, the number of white blood cells, Platelets and the total amount of hemoglobin in blood. Hematocrit (HCT) is the fraction of blood composed of red blood cells.

A Complete Blood Count normally includes the following components:

• Red Blood Cell Count (RBC) (also known as Erythrocyte Count)
  
• Red Blood Cell Indices : MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Hemoglobin) and MCHC (Mean Corpuscular Hemoglobin Concentration)
  
• Hemoglobin (Hgb)
  
• Hematocrit ( HCT)
  
• White Blood Cell count (WBC or leukocyte count)
  
• Platelet count (thrombocyte count)
  

A CBC test provides information on measurements such as average red blood cell size or MCV, Hemoglobin per blood cell or Mean Corpuscular Hemoglobin MCH, hemoglobin concentration or the amount of hemoglobin relative to the size of the cell, per red blood cell or MCHC and platelet count.

Why Complete Blood Count test?

This is a complete lab test and is used to detect or monitor different health conditions. A doctor may require this test for various reasons: As a routine check up

If the patient exhibits symptoms such as fatigue, weight loss, fever or any other signs of infection, weakness, bruising, bleeding or signs of cancer

Blood count results may change if you are receiving treatment for medicines and radiation

To monitor any chronic health problem that can change your blood count results such as chronic kidney disease.

Results of CBC

Though blood count may vary with altitude, in general the normal ranges are given below. But it should be noted that these ranges may vary slightly from one laboratory to another. Various laboratories use varied measurements or test different samples. It is best to have it interpreted by a health care provider.

Normal Values:

Red blood cell indices:

MCV (Mean Corpuscular Volume): 80 to 95 femtoliter
MCH (Mean Corpuscular Hemoglobin): 27 to 31 pg/cell
MCHC (Mean Corpuscular Hemoglobin Concentration): 32 to 36 gm/dL

RBC (erythrocyte) count:

Male: 4.7 to 6.1 million cells/mcL
Female: 4.2 to 5.4 million cells/mcL

WBC (leukocyte) count:

4,500 to 10,800 cells/mcL

Hematocrit:

Male: 40.7 to 50.3%
Female: 36.1 to 44.3%

Hemoglobin:

Male: 13.8 to 17.2 gm/dL
Female: 12.1 to 15.1 gm/dL

Platelet (thrombocyte) count:

150,000 to 450,000/dL

What abnormal results mean?

An abnormal result means elevated RBC, hemoglobin or Hematocrit. These may be due to various factors including lack of adequate water and fluids due to severe diarrhea, excessive sweating or if diuretics are used to treat hypertension.

Low RBC, hemoglobin or hematocrit is also a sign of which result due to blood loss on account of heavy menstrual periods over long periods of time, bone marrow failure from radiation, infection or tumor, Hemolysis or breakdown of red blood cells, chronic kidney disease, ulcerative colitis or rheumatoid arthritis, leukemia, multiple myeloma, long term infections such as hepatitis, poor diet and nutritional deficiencies of iron, Vitamin B6, Vitamin B12 and folate.

High levels of Hematocrit can be the result of dehydration, diarrhea, erythrocytosis or myeloproliferative disorders such as Polycythemia Vera.

Lower than normal white blood cell count, or Leukopenia (Leucopenia), can be the result of alcohol abuse and liver damage, autoimmune diseases, bone marrow failure due to infection, tumor, radiation or fibrosis, chemotherapy medicines, disease of liver or spleen, enlarged spleen, infections caused by viruses such as AIDS or medications.

High WBC count is called leukocytosis which can result from certain medicines such as corticosteroids, infections, diseases such as rheumatoid arthritis or allergy, leukemia and severe emotional and physical stress, tissue damage

High platelet count may be due to bleeding - diseases such as cancer, iron deficiency, problems with the bone marrow.

Low platelet count may be due to anemia, disorders where platelets are destroyed during pregnancy, enlarged spleen, bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis), Chemotherapy medicines used to treat cancer.

Disease of the platelets is known as Thrombocytopathy, which could be due to lower Platelet counts (a condition called as Thrombocytopenia or Thrombopenia), or due to a decrease in function (called as Thrombasthenia) or an increase in the number of platelet (addressed as Thrombocytosis). Normal platelet counts do not necessarily indicate normal functioning. In some cases the platelet counts may appear normal but the platelets themselves are dysfunctional. Aspirin inhibits cyclooxygenase-1 (COX1) which results in the disruption of platelet function affecting coagulation. Normal platelet function will be restored only when the affected platelets have been replaced which can take a week.

Precaution : At the time of drawing the blood, it is necessary to clean the venipuncture site with alcohol.

Platelets

Platelets or thrombocytes are cell fragments found in the blood with an average life span of about 5- 9 days. Typically a healthy adult has about 150,000 to 450,000 platelets per micro liter of blood. Platelets are crucial for the clotting process since they are involved in hemostatis. If the platelet count is too high or low, it can be indicative of some disorders. Abnormally high platelet count can lead to myocardial infarction, pulmonary embolism or a stroke. Very low platelet count can lead to excessive bleeding. Low platelets can happen due to medications, leukemia, hemolytic anemia or chemotherapy. Abnormally high platelet count can be due to anemia, thrombocythemia or recent spleen removal.

Myelodysplastic Syndrome

Myelodysplastic syndrome or MDS refers to a group of blood disorders caused by defective blood cell production in the bone marrow. Bone marrow produces immature blood cells called blasts, which over a period of time develop into mature blood cells and divide themselves into red blood cells, white blood cells and platelets. In Myelodysplastic syndrome, these blasts fail to mature and either die in the marrow itself or soon after they reach the blood stream. When there are not enough healthy blood cells, the body becomes weak and is susceptible to infections. MDS is not a cancer, however, in 20 to 30% of patients, the condition may progress itself into cancer and thus this condition was earlier called preleukemia.

Causes of Myelodysplastic syndrome

Based on causes, Myelodysplastic syndrome can be classified into primary MDS and secondary MDS. Myelodysplastic syndrome presenting itself without any known cause is called primary MDS. Myelodysplastic syndrome may also occur due to some known reasons such as history of cancer treatment involving radiation and chemotherapy, exposure to certain industrial chemicals and smoking. When the cause of the MDS condition is known, it is called secondary Myelodysplastic syndrome. Identifying the type of MDS is vital to the treatment as primary MDS has better prognosis when compared to secondary MDS.

Symptoms

Myelodysplastic syndrome does not cause any symptoms in the initial stages of the disease. However, the following warning signs may show up as the disease starts to progress.

• Fatigue due to anemia
  
• Frequent infections due to damaged immune system
  
• Shortness of breath
  
• Paleness
  
• Easy bruising or bleeding can occur due to low platelet count.
  
• Small red spots just under the skin.
  

Diagnosis and treatment

MDS is diagnosed with the help of blood tests and bone marrow tests. A complete blood test is done to understand the different blood counts. However, blood tests alone cannot detect MDS. Bone marrow tests are conducted to confirm the presence of Myelodysplastic syndrome. This procedure involves taking bone marrow samples from the pelvic bone of the patient by inserting a needle under local anesthesia. Once MDS is determined, the following methods are followed to treat the condition.

• Chemotherapy drugs
  
• Blood transfusion to treat anemia and low platelet count.
  
• Using medications called growth factors to allow the bones marrow to make more blood cells.
  
• Antibiotics to treat infections
  
• Stem cell transplant, an option that promises a cure to MDS, yet not widely adopted, as not many candidates qualify for this method. This method involves destroying the existing cells in the bone marrow via chemotherapy and radiation and infusing the stem cells from the donor.