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Causes of Low Hematocrit and Hemoglobin

Causes of Low Hematocrit and Hemoglobin

Low hematocrit and hemoglobin levels signify a decrease in red blood cells (RBCs) in the body. This HealthHearty article gives you an overview of the symptoms and possible causes that could trigger the same.
Rahul Thadani
Last Updated: Apr 3, 2018
Did You Know?
There are about one billion red blood cells in two to three drops of blood, and for every 600 red blood cells, there are about 40 platelets and one white cell.
― American Red Cross
Both hemoglobin and hematocrit are linked with red blood cells (RBCs). Hemoglobin (Hb) is the protein found in RBCs that carries oxygen to the entire body. On the other hand, hematocrit is the measurement of the amount of RBCs present in the total blood volume. The values of both these components can be determined by conducting a complete blood count (CBC) test, as both are based on plasma volume.

The normal acceptable level of hemoglobin in men and women ranges between 14 to 18 g/dl and 12 to 16 g/dl respectively; g/dl being the abbreviation for the measuring unit 'grams per deciliter'. The hematocrit is reported as a percentage of the volume of red blood cells in 100 ml of blood. The normal range in men is 40 to 54%, while for women the values range between 36 to 48%. Note that the values may vary from one medical authority to another. Usually, a 7% difference (in higher or lower values) is seen among different diagnostic centers. Therefore, it is essential to clarify the meaning of the report results from the respective medical professional.
Symptoms that May Indicate Lower Levels
Deficiency of RBCs is medically known as anemia. Your doctor would usually prescribe a blood test when he/she feels that your signs and symptoms point towards an iron deficiency or anemia. The following are some of the common symptoms that would substantiate an RBC deficiency.
  • Constant fatigue and tiredness
  • Faster heart palpitations that suddenly crop up
  • Shortness of breath
  • Paleness of skin
  • Hair loss
  • Worsening of heart problems
  • Fainting attacks

The intensity of symptoms also depends upon the severity of anemia, and the individual's body type. People with chronic anemia will display less intense symptoms because their bodies have become accustomed to the condition. On the other hand, people having acute anemia (rapid anemia) will experience symptoms more intensely.
Possible Reasons behind Low Levels
The causes of anemia can be grouped in two general categories. They are: (1) When the production of the red blood cells in the body gets disrupted or stops completely; and (2) When there is an unpredicted amount of blood lost from the body, or the RBCs are getting destroyed.

The means of discerning the hematocrit levels in the body are Mean Corpuscular Volume (MCV) and Red Cell Distribution Width (RDW), and these help doctors determine if a person is having low hemoglobin and hematocrit levels in the body. The MCV determines the actual size of the blood cells, and the RDW determines the differences in size between all the red blood cells. If a person shows low MCV levels but high RDW levels, then the condition is being caused by a chronic iron deficiency. On the other hand, a normal RDW level accompanying a low MCV level signifies a different channel of blood loss, most notably through a hemorrhage in the body.
It is not always that the lower values are a matter of concern. There are some instances where a low RBC count is absolutely normal. For instance, pregnancy usually causes decreased hematocrit values because of the presence of extra fluid in the blood. Even women who are of childbearing age, tend to have low hemoglobin and hematocrit levels during menstruation. The serious causes behind this condition are explained as under.
Thalassemia: It is an inherited blood disorder that runs in families. This disorder leads to destruction of large numbers of RBCs and low hemoglobin, resulting in anemia.

Hemolytic Anemia: In this type of anemia, the red blood cells in the body get destroyed and removed from the bloodstream before their lifespan is over. The bone marrow becomes incapable to produce adequate amount of red blood cells fast enough to meet the body's demand.

Sickle Cell Anemia: It is an inherited genetic disorder where the RBCs have a sickle-like shape and tend to die within 10-20 days, rather than living an entire lifespan of 120 days. As a result, a deficiency is created in the body, as the bone marrow is unable to create new RBCs fast enough.

Bone Marrow Disorders: As the red blood cells are made in the bone marrow, it is crucial for it to be healthy enough to perform the task. Diseases including leukemia, lymphoma (that spreads to the bone marrow), aplastic anemia (where the bone marrow stops making blood cells), and the like, come in this category.

Bone Marrow Damage: Damage to the bone marrow can be caused due to certain infections, medications, toxins, drugs, and therapies such as chemotherapy and radiation exposure.

Internal Bleeding: Internal bleeding, be it acute or chronic in nature, could also cause anemia. It may occur due to ulcers, polyps, or cancer, at any area of the body, though it is commonly seen in the digestive tract.

Kidney Diseases: The kidneys play a crucial role in the production of red blood cells. They produce a hormone called erythropoietin (EPO), which indicates the bone marrow to produce RBCs. A kidney disease or failure results in decreased levels of EPO, affecting the production of RBCs as well.

Nutritional Deficiencies: Lack of adequate amounts of certain vitamins and minerals including iron, folic acid, vitamin B12, etc., due to a poor diet (be it among adults or children), can affect the hemoglobin and hematocrit levels in the blood.

Other Causes: Other causes include chronic inflammatory diseases or infections, HIV/AIDS, rheumatoid arthritis, or a having undergone a recent surgery or serious injury.
Treatment Options
Considering that there are varied reasons behind low hematocrit and hemoglobin levels, the exact treatment would depend upon the underlying cause. While some controllable causes can be treated easily, others may need an in-depth medical intervention. For instance, a nutritional deficiency can be rectified by introducing some dietary changes and nutritional supplements. Also, if it is a medication that has been altering the levels, then stopping its consumption or opting for an alternate medicine will help. However, if the cause is something as serious as cancer, a severe form of anemia, or a chronic disease, then crucial measures including surgery, blood transfusion, and more, will be needed.
An abnormal blood report isn't always taken seriously by many. Agreed that the underlying trigger is not always life-threatening in nature, however, considering the many possibilities that come along with a decrease in red blood cells, it is highly recommended to get to the causal trigger behind the same as soon as possible. Only thorough testing and diagnosis will pave way for an accurate and timely treatment. Take care.
Disclaimer: This HealthHearty article is meant for informational purposes only and should not be considered as a replacement for expert medical advice. Kindly consult a trusted physician for thorough and accurate diagnosis, followed by an appropriate treatment plan.