The Red Blood Cell System
The elements that allow for the assessment of the red blood cell system are:
- RBC (red blood cell) count
- Hematocrit (the ratio of blood cell volume to whole blood volume)
- Hemoglobin (Hb) concentration
- MCV (mean corpuscular volume)
- MCH (mean corpuscular hemoglobin)
- MCHC (mean corpuscular hemoglobin concentration)
- RDW (red cell distribution width)
These factors help doctors rule out anemia and assess hemoglobin production. Evaluating red blood cells helps determine cell size, hemoglobin content, and anisocytosis, which are vital for a comprehensive diagnosis.
The White Cell System
The elements describing the white blood cell system are:
- Total white blood cell count (WBC)
- Number of granulocytes
Also, assessment of the granulocyte fraction, including:
- NEUT (neutrophils)
- EOS (eosinophils)
- BASO (basophil granulocytes)
- Number of lymphocytes, T lymphocytes, and B lymphocytes
- NK cells – non-standard
- MONO (monocytes)
Platelets
The last element of the morphological examination is the determination of the number of platelets. Those include:
- PLT (platelet count)
- MPV (mean plate volume)
- PDW (determines the variability – diversity – of platelet volume in the blood)
- P-LCR (shows the number of so-called large tiles)
Indications
Regular blood counts are essential and should be conducted at least annually. Moreover, there are specific indications for the morphology test, including but not limited to:
- Initial diagnosis of anemia or polycythemia
- Differentiation of anemia types
- Monitoring the efficacy of anemia treatment
- Assessment of bone marrow hematopoietic function
- Evaluation of a patient’s condition post-hemorrhage
- Diagnosis of immunodeficiencies and inflammatory or infectious diseases
- Identification of proliferative diseases such as leukemia
- Bleeding diagnostics
- Assessment of the coagulation system
- Monitoring anticoagulant therapy
Contraindications
To perform a complete blood count, blood is taken in a small amount, which does not affect the patient’s condition. For this reason, there are no contraindications to its performance.
Blood for the test is taken in a sitting position, sensitive people should be in a lying position.
Information to report before the test include:
- Tendency to bleed (bleeding diathesis)
- Tendency to faint during blood collection
- Currently taking medications
Preparations
For the morphology result to be reliable, you must properly prepare for the test.
When getting ready for the test, it’s important to remember that the blood morphology should be taken in the morning, and you should be fasting. This means no eating or drinking anything after dinner the night before the test, ideally for 12 hours. Sometimes the test can be done 5-6 hours after the last meal – inform the doctor about this as it may affect the test results due to postprandial leukocytosis, a temporary increase in white blood cells after a meal.
Before the morphology, it’s best to avoid stress and strenuous exercise and ensure you get a good night’s sleep. Also, it’s recommended to abstain from alcohol for 2-3 days before the test.
Ideally, the blood morphology should not be done during menstruation, fasting, or overeating. To obtain accurate results, it’s advisable to schedule the test at least 3 days before or after menstruation.
Before collecting blood for morphology, inform your doctor about any medications you take. If possible, they should be discontinued during the test and resumed after blood collection. These medicines include:
- NSAIDs – non-steroidal anti-inflammatory drugs
- Diuretics
- Oral antidiabetic drugs
- Sulfonamides
- Cephalosporins
- Acetylsalicylic acid – ASA
- Antiepileptic drugs
These may affect your platelet count.
Blood Composition In A Healthy Person
The interpretation of morphology test results relies heavily on the reference values provided by a specific laboratory. This is because some parameters can be assessed using different methods. It’s important to note that a doctor’s analysis isn’t just about ensuring each indicator falls within the laboratory’s specified range. Age, gender, existing medical conditions, and medications also play a crucial role. Children have different norms than adults, and gender further influences the assessment. Additionally, the reasons for ordering and conducting the test are significant, as the results are evaluated based on the symptoms reported by the patient.
Red Blood Cells
Normal range of red blood cells in morphology in women is 4 to 5 million cells/mcL and in men is 5 to 6 million cells/mcL.
This test determines the concentration of red blood cells in 1 µl of blood. Red blood cells, which have a disc-shaped, biconcave form, are crucial in transporting life-sustaining oxygen from the lungs to all body tissues and carrying carbon dioxide from the tissues to the lungs for excretion into the atmosphere.
Their production in the bone marrow requires various essential micro- and macroelements, the most important being iron, vitamin B12, and folic acid. A single red blood cell has a lifespan of 120 days, after which it is broken down in the reticuloendothelial system located in the spleen and liver.
Causes Of An Increased Number Of Red Blood Cells
An elevated erythrocyte count, or erythrocytosis, can be attributed to various factors. Dehydration can lead to an increase in erythrocytes due to the thickening of the blood, resulting in a higher percentage of erythrocytes in its volume. Chronic hypoxia also prompts the body to produce more erythrocytes, as they serve as carriers of oxygen. This response is mediated by the kidneys, which increase the production of erythropoietin (EPO), a hormone that stimulates erythrocyte production in the bone marrow in response to hypoxia.
Hypoxia may occur under several circumstances, including exposure to high altitudes where the lower air pressure hinders gas exchange in the alveoli. Smoking cigarettes introduces carbon monoxide, which binds to hemoglobin with a much greater affinity than oxygen, leading to the formation of carboxyhemoglobin instead of oxygenated hemoglobin. This diminishes the blood’s oxygen-carrying capacity. Additionally, conditions such as obstructive sleep apnea (OSA) cause recurrent pauses in breathing during sleep, depleting oxygen reserves in erythrocytes and resulting in hypoxia.
Certain medical conditions, like congenital heart defects, lung diseases, and rare disorders, can also lead to hypoxia and subsequently elevate erythrocyte production. Furthermore, polycythemia vera, a rare disorder characterized by uncontrolled erythrocyte overproduction and tumors that secrete erythropoietin, are potential causes of increased erythrocyte levels. Lastly, the use of glucocorticoids during steroid treatment or in Cushing’s syndrome can also contribute to elevated hematocrit values.
Causes Of An Increased Number Of Red Blood Cells
Insufficient production of erythrocytes results in a condition known as anemia. This condition can be classified into several types:
- Deficiency anemia – most commonly caused by a lack of iron, vitamin B12, or folic acid, essential for erythrocyte production. Iron deficiency is often due to chronic bleeding, malabsorption syndromes, or increased demand during puberty or pregnancy.
- Anemia caused by chronic diseases—the immune system’s response to various infections, cancer, or autoimmune diseases can lead to reduced erythrocyte production.
- Post-hemorrhagic anemia – sudden or chronic blood loss causes dilution of blood as extracellular fluid enters the bloodstream, reducing the hematocrit value.
- Hemolytic anemia – caused by premature breakdown of erythrocytes. It is categorized as congenital if the breakdown results from abnormal erythrocyte structure (e.g., congenital spherocytosis, thalassemia) and acquired if a factor causes breakdown (e.g., anti-erythrocyte antibodies, artificial heart valve, infections).
- Aplastic anemia – occurs due to damage to the bone marrow, the site of erythrocyte production, caused by exposure to ionizing radiation, toxic chemicals, or certain drugs.
Overhydration causing anemia is an uncommon occurrence.
White Blood Cells
The normal white blood cells range is 4500–10,000 cells/mcL.
Leukocytes are blood cells that are part of the immune system. They fight pathogens such as viruses and bacteria. Their lifespan ranges from a few days to even 20 years.
Causes Of An Increased Number Of White Blood Cells
An elevated total leukocyte count (leukocytosis) usually indicates an ongoing infection in the body. When the body fights an infection, immature leukocytes are released from the bone marrow into the bloodstream to combat the pathogen more effectively, causing the count to rise to as high as 20,000/µl.
A significant surge in the leukocyte count (>30,000/µl) could indicate cancer, such as leukemia or lymphoma, although this is uncommon. A minor, temporary increase may occur if the guidelines for preparing for a blood count are not followed, such as eating a meal or exercising before the test.
Causes Of A Dicreased Number Of White Blood Cells
Those frequently include:
- Beginning of infection – at the very beginning of the infection, leukocytes circulating in the blood gather at the site of infection. Before the bone marrow releases leukocytes to restore the proper number of them in the blood, a blood test may show leukopenia, then called pseudoleukopenia
- A previous acute viral infection, such as a cold or flu
The rare causes of dicreased leukocytes number are:
- Severe malnutrition (anorexia)
- Treatment with glucocorticoids and other immunosuppressive drugs, some antipsychotic drugs
- Blood cancers (leukemia)
Platelets
The normal range for platelets is 140,000–450,000 cells/mcL.
Platelets, also known as thrombocytes, play a crucial role in blood clotting. They combine with a protein called fibrin at the site of a bleed to form a mesh that prevents excessive blood loss. A platelet count of 50,000/µl is generally considered sufficient for properly functioning the coagulation system. A low platelet count is often a common occurrence, sometimes due to a long interval between blood collection and analysis. However, it can also be linked to a deficiency in vitamin B12 and folic acid, damage to the bone marrow where they are produced, or rare disease syndromes leading to excessive destruction of platelets.
What Does The Blood Morphology Result Show?
Abnormal values for each parameter in a medical test could indicate different health issues. However, it’s essential to consider the overall picture, as each parameter relates to the functioning of specific body systems.
A high count of white blood cells (leukocytosis) often indicates ongoing inflammation, but it could also result from past injuries. Conversely, a low count (leukopenia) is commonly linked to certain medications or past viral infections.
Interpreting red blood cell results is more intricate. Generally, a high count may point to hypoxia or dehydration. At the same time, a low count is often associated with deficiency anemia or chronic diseases and could also result from a previous hemorrhage.
An increased platelet count (thrombocytosis) can be caused by various factors, including iron deficiency anemia, chronic infectious or inflammatory diseases, and alcoholism, as well as the use of certain medications.
Independent interpretation of morphology results can lead to unnecessary stress or fear. Due to the complexity involved, it’s crucial to leave the analysis to medical professionals.
Sources
- Histology, Red Blood Cell. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK539702/ - Histology, White Blood Cell. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK563148/ - Physiology, Platelet. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK470328/ - Anatomy and Morphology. Science Direct.
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/anatomy-and-morphology - Blood Tests. NIH.
https://www.nhlbi.nih.gov/health/blood-tests - Polycythemia. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK526081/ - Hypoxia. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK482316/ - What Is Anemia?. NIH.
https://www.nhlbi.nih.gov/health/anemia - Leukocytosis. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK560882/ - The Etiology and Management of Leukopenia. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2154209/ - Thrombocytopenia. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK542208/
