Decreased hematocrit, values and causes

Hematocrit is the percentage of blood volume taken up by red blood cells and considered an integral part of the blood test.

Hemoglobin is a metalloproteinase in red blood cells.

Hemoglobin is an important indicator of the presence or absence of anemia or the lack of red blood cells, hemoglobin, or both.


Normal values of haematocrit

Hematocrit levels are higher in men than in women. Another factor that affects hematocrit is age.

Hematocrit in adults

According to the National Institute of Health, normal hematocrit levels are in the ranges:

  1. Women: 36, 1-44, 3%
  2. Men: 40, 7-50, 3%

Men have higher hematocrit and hemoglobin levels than women because testosterone stimulates the renal production of EPO (erythropoietin) and thus red blood cells.

Hematocrit in children

  • In a newborn: 42-65%
  • For a child from 1 to 2 months: 28-55%
  • 3 months – 6 months: 29-41%
  • 6 weeks – 1 year: 31-41%
  • 1 year – 5 years: 31-44%
  • 5 years – 11 years: 35-44%
  • In a healthy adolescent of 12-18 years: 36-49%
  • In a healthy adolescent of 12-18 years: 36-46%.

Source: UI Diagnostic laboratories – University of Iowa

Premature babies have a decreased hematocrit because of the not yet developed lungs.

When should one be worried about lowered hematocrit?

Anemia is a disease in which haemoglobin drops below 7 mg/dl.

Often older people ask me whether a decreased or an elevated hematocrit is better. In fact, both types indicate different conditions and one should try to stay within a normal range.

Symptoms of decreased hematocrit

A decreased hematocrit is characterized by symptoms such as:

  1. Shortness
  2. Sleep apnea
  3. Constant fatigue,
  4. Weakness.

If the hematocrit is only slightly lowered, the symptoms are mild.

The risks and complications are explained by the absence of O.2 (oxygen) in the body’s cells because fewer erythrocytes correspond to a lower amount of circulating hematocrit.

Causes of decreased hematocrit

Blood tests that indicate a lowered hematocrit cannot be ignored and are a cause for concern.

The main causes are listed below.


Anemia causes a significant decrease in the number of red blood cells (RBCs).

If the number of RBCs is too low, there is a sharp drop in hematocrit levels.

A person with low hematocrit levels is called anemic.

Anemia is usually diagnosed in people with iron deficiency, but there are other conditions that can cause anemia, such as:

  1. Coeliac disease
  2. lack of vitamin B12 and folic acid,
  3. Leukaemia
  4. Autoimmune diseases
  5. Thalassemia.

A haematocrit between 32% and 35% is considered a mild case of anaemia, but if the values fall below 28%, there is a higher chance of:

  1. Constant fatigue,
  2. Lack of energy.


The term hemolysis refers to the process of destruction of red blood cells and is used to indicate the premature death of red blood cells.

In other words, hemolysis reduces the circulation time of these cells and the number of RBCs.

The result is a decreased hematocrit value in the body.


Vitamin B12, iron and folic acid are important for the production of RBC.

A deficiency of these nutrients can lead to decreased levels of red blood cells and hematocrit.

In this case, the RDW (erythrocyte distribution width) value is also high, which means that the erythrocytes have a very different size.


Any internal or external bleeding can reduce hematocrit, for example, internal bleeding due to an ulcer in the digestive tract.

Also, the abundant blood loss from a deep skin injury, during surgery or during menstruation can be responsible for a decreased hematocrit value.

Renal failure

Below-norm hematocrit levels may indicate renal insufficiency, in which the kidneys are no longer able to maintain their function.

Renal insufficiency may include:

  1. Acute (rapid decrease in kidney function),
  2. Chronic and gradual.

In both cases, the space occupied by the blood cells in the blood is significantly reduced.

Chemotherapeutic drugs

Chemotherapeutic drugs, which are often used to treat tumors, can have a negative effect on the normal number of erythrocytes.

These drugs are used to kill tumor cells, but they can also destroy healthy red blood cells.

This leads to a reduction in the volume of erythrocytes (red blood cells) in the blood.

Other medications

Some medications can affect the percentage of hematocrit.

People who take antibiotics such as chloramphenicol and penicillin have a greater risk of developing anemia, which could decrease hematocrit.

According to a study by Wongnoi R et al. (Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang-Mai University, Chiang-Mai, Thailand), the drugs responsible for this include those that interfere with folate metabolism, such as antiretroviral drugs for the treatment of HIV infection.

Side effects of antiviral drugs also include:

  • A decrease in hemoglobin,
  • A decrease in hematocrit,
  • leukopenia (low white blood cell count),
  • Thrombocytopenia (decreased platelet count) in immunosuppressed patients.

Myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are a group of different conditions in which the bone marrow does not develop an adequate amount of healthy blood cells.

In MDS, the stem cells cannot mature, accumulate in the bone marrow, or have a reduced lifespan, resulting in a lower number of mature cells in the blood.

The decreased number of blood cells (also called cytopenia) is a characteristic feature of MDS and responsible for various disorders:

  1. Infection;
  2. Anaemia;
  3. Spontaneous bleeding;
  4. Ecchymoses or bruises.

Anemia (decreased number of red blood cells), neutropenia (decreased number of white blood cells) and thrombocytopenia (decreased number of platelets) are the main types of cytopenia.

Often, myelodysplastic syndrome occurs together with anemia.

Anemia is characterized by a decrease in hematocrit and low hemoglobin (blood protein that transports oxygen to tissues).

Some athletes of sports such as cycling and running use doping substances that increase hematocrit, as this allows them to maintain a high speed on the bike for a long time.

The most common symptoms of myelodysplastic syndrome include:

  1. Fatigue;
  2. Weakness;
  3. Athletes may notice a significant reduction in performance;
  4. Vertigo.

Other causes of decreased hematocrit:

  1. bone marrow diseases;
  2. Chronic inflammatory diseases;
  3. Hemolytic anemia;
  4. leukemia (tumor of the bone marrow);
  5. Lymphoma.

Hemoglobin levels and decreased hematocrit

Decreased hematocrit and decreased hemoglobin can be caused by various diseases.

  • One of the most serious causes is hemorrhage.
    Hemorrhage can occur internally or externally.
    Hemorrhage causes significant blood loss, which can lead to excessive loss of erythrocytes.
    In such cases, it may be useful to do a blood test to control the mean corpuscular volume.
  • One of the most common causes of decreased hemoglobin and hematocrit is anemia.
    Anemia is a disease in which haemoglobin drops below 7 mg/dl.
  • Other causes include leukemia, which is a tumor that causes changes in the number of blood cells.
  • The drop in hematocrit can occur mainly in the last trimester of pregnancy, because the plasma volume increases.
  • Menopause does not affect hematocrit.

Other blood values that may be altered

Low white blood cell count (neutropenia)

The decrease in the number of white blood cells reduces the body’s resistance to bacterial infections.

Patients with neutropenia (decreased number of neutrophils) may be susceptible to infection:

  1. On the skin,
  2. In the paranasal sinuses (symptom is also nasal congestion),
  3. In the lungs (symptoms are coughing and difficulty breathing),
  4. In the urinary tract (symptoms are a painful and frequent micturition).

Along with the infections, fever may occur.

Low platelet count (thrombocytopenia)

Patients with thrombocytopenia bleed and bruise even after minor blows and scratches. Nosebleeds are a common symptom.

Often the gums bleed, especially after brushing your teeth.

Check for signs of other anomalies

You have to compare all the abnormal values from the blood tests to find out what condition the patient has.

If the patient has a decreased hematocrit and at least one other abnormal value, the following diagram can help to make a diagnosis.

Data outside the values

Possible diseases

Leukocytosis or elevated white blood cells Leukemia or lymphoma Decreased lymphocytes Autoimmune thyroiditis or leukemia Decreased hemoglobin Anemia Decreased ferritin and iron Iron deficiency anemia Increased bilirubin Hemolytic, pernicious or sickle cell anemia Increased serum iron Hemolytic and pernicious anemia Increased MCHC (concentration of hemoglobin) Haemolytic anaemia Decreased MCV (medium corpuscular volume) Thalassemia High ESR inflammation

Hematocrit in pregnancy

In pregnant women, hematocrit levels vary by trimester and differ from those of non-pregnant women.

Specific ranges for the trimester and age are therefore given in relation to pregnant and normal women.

Since people who live at higher altitudes have higher blood levels, the values of Hb or Hkt are automatically adjusted to the corresponding level.

Trimester of pregnancy

trimester of pregnancy Hemoglobin
First 11.0
Second 10.5
Third 11.0


trimester of pregnancy Haematocrit
First 33.0
Second 32.0
Third 33.0
Age Hemoglobin Haematocrit
12 – 15 years 11.8 35,7
15 – 18 years 12.0 35,9
≥ 18 years 12.0 37,7

Pregnant women are at risk of developing anemia due to the constant demand for iron from the fetus.

In pregnant women, hemoglobin (Hb) or hematocrit (HCT) levels decrease during the first and second trimesters due to the increase in blood volume.

Scientific studies have shown that during pregnancy, the incidence of anemia in the third trimester is much higher.

Pregnant women with an adequate iron balance experience a gradual increase in Hb and Hkt in the third trimester to pre-pregnancy levels.

Blood tests after birth must be done at 4 weeks or 28 days when the Hb and HCT have returned to the levels that existed before pregnancy or the first trimester.

After delivery, maternal hemoglobin should increase, as the increased blood mass decreases.

What to do in case of reduced hematocrit?

Therapy depends on the underlying disease. Accordingly, the doctor prescribes the most appropriate treatment of the disorder that causes the lowered hematocrit.

Often therapy is not necessary because the values of hematocrit depend only on the volume of blood and spontaneously normalize.

For severe cases with too low hematocrit, treatment consists of a blood transfusion.

If the hematocrit levels are too low, you must not donate blood.

What should you eat? Diet and nutrition for decreased hematocrit

Foods that contain iron and vitamin C

Those who suffer from iron deficiency anemia can add iron-containing foods to their food. Foods that contain mainly iron are:

  1. red meat;
  2. calf’s liver;
  3. Eggs;
  4. Beetroot;
  5. Yeast;
  6. Molasses;
  7. Raisins;
  8. spinach and other dark green leafy vegetables;
  9. Some foods such as bread and cereals for breakfast, fortified with iron.

Vitamin C improves iron absorption from the digestive tract.

It is mainly found in:

  1. Citrus;
  2. Fruit juices;
  3. Broccoli;
  4. Cauliflower;
  5. Tomatoes.

One should drink orange juice or eat foods high in vitamin C along with iron-rich foods.

Foods containing folic acid

Absorption problems of the digestive tract due to aging or alcoholism can lead to megaloblastic anemia.

This is caused by a lack of folic acid, which is a vitamin of the B group and necessary for the production of normal red blood cells. It is present in some foods, for example:

  1. Asparagus;
  2. Orange juice;
  3. Tomato juice;
  4. Broccoli;
  5. Spinach;
  6. Chickpeas;
  7. whole grain cereals;
  8. fortified foods;
  9. Peas.

Foods containing vitamin B12

Foods high in vitamin B12 include:

  1. Liver;
  2. Poultry;
  3. red meat;
  4. Tuna;
  5. Eggs;
  6. Cheese;
  7. Milk;
  8. Yoghurt;
  9. Breakfast cereals and other foods fortified with vitamin B12.

Diet recommended by naturopathy

Based on the blood type diet, anemia is caused by cereals, especially gluten-containing ones, which reduces the absorption of minerals and vitamins in the intestine.

One should therefore avoid:

  • Bread
  • Noodles
  • Pizza
  • Sweet
  • Cracker
  • Other cereal products containing gluten (oats, spelt, wheat and kamut).

According to hygienism, anemia due to vitamin and iron deficiency is not due to a lack of food, but to excessive nutrition.

In fact, there are people who have been able to improve the blood levels of iron and red blood cells through fasting.

Hygienists recommend vegan or raw food, simple dishes and natural foods.

According to this theory, humans are destined to eat mainly fruits, because their intestines resemble those of other herbivorous animals such as chimpanzees.

The diet should consist of foods that are digested quickly, such as:

  1. Raw vegetables,
  2. Fruit
  3. Potatoes.

In addition, seeds and nuts (walnuts, almonds, etc.) are recommended because they contain a lot of proteins.

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