Hematocrit values are analyzed to identify underlying medical conditions that are related to blood. Red blood corpuscle percentage in the blood composition plays a significant role in the normal physiological activity carried out by the body. Variations in these values indicates disease or malfunction in the body. Hematocrit value is estimated along with hemoglobin values to correlate the association of the red blood cells with the respective disease type. The hematocrit or hct is expressed as a percentage. Hence the complete blood counts play an important role in the effective diagnosis.
The normal ranges of hct values are 38% to 46% for women and 42% to 54% in men. It can vary in children from infancy to 10 years. Hematocrit blood test is recommended by physicians when the patient is clinically symptomatic of conditions related to anemia. After the patient history examination, the hematocrit is recommended to identify the type of anemia. Anemic patients have classical symptoms such as pale appearance, blurred or disturbed vision, and shortness of breath, lethargy and dizziness. Hematocrit values determine the cause of low RBC percentage and reduced hemoglobin values in association with underlying disorder. In some cases low RBC levels may indicate hemolytic anemia. Other conditions such as sickle cell anemia and thalassemia are also diagnosed by analyzing the hematocrit values. Hematocrit values also determine the presence of inflammatory diseases and conditions such as cancers, polyps and ulcers. Other conditions which lead to low RBC and hemoglobin levels include nutritional deficiency, congenital heart disease, chronic obstructive pulmonary disease, trauma to the kidneys and genetic disorders. Higher Hematocrit percentage is often noticed in chronic smokers and those living in higher altitudes. Another cause for high hct is dehydration
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.
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
Male: 40.7 to 50.3%
Female: 36.1 to 44.3%
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.
Polycythemia is a rare blood disorder in which the bone marrow produces excessive red blood cells than the usual amount and thereby thickens the blood. Polycythemia along with red blood cells may also increase white cells and platelets count. Polycythemia occurs due to a gene mutation called as JAK2V617F. The cause of this mutation is still not identified. Patients with Polycythemia condition show increased levels of hematocrit (the ratio of the volume of red blood cells to the total volume of blood) or hemoglobin (RBC count).
Primary Polycythemia is congenital and is known to occur due to a defective mechanism developed in the bone marrow. Though research is not able to pin point the exact cause of the impairment, specific gene mutation in bone marrow is said to be causing primary Polycythemia.
Secondary Polycythemia is an acquired condition, normally developed by people living in high altitude region. As these areas have poor oxygen levels, the body produces more blood cells to make up for oxygen. Smoking, lung infections, kidney tumors and cysts also lead to Polycythemia.
Symptoms of Polycythemia
Polycythemia develops gradually and may not show any symptoms initially. It may be present in the body for years and bearer may not be aware of the condition. Most often it is revealed during the blood tests carried on for some other condition. However following symptoms indicate the presence of Polycythemia:
1. Itching following a bath with warm water and redness of the skin.
2. Headache, tiredness and dizziness.
3. Breathing difficulty especially in a lying posture.
4. Enlarged spleen and bloated stomach.
5. Tingling sensation in arms and legs.
6. Excessive sweating.
Treatment of polycythemia
Polycythemia requires prompt treatment, else it may lead to blood clots and increased risk of stroke. Most often Phlebotomy (removal of small amounts of blood) is the first step in treating polycythemia. The frequency of the Phlebotomy depends upon the severity of polycythemia. Along with Phlebotomy, patient may be put on medication (hydroxyurea or anagrelide) to reduce the bone marrow ability to produce excess red blood cells. Sometimes doctor may also prescribe aspirin to prevent blood clots and aspirin will also take care of the burning sensation in the extremities.