What Is a Hemogram? Why Is a Complete Blood Count Test Performed?

Created: 13.04.2026  ·  Last Updated: 09.07.2026  ·  Category: Internal Medicine  ·  Prepared by Academic Hospital Web and Editorial Board.

What Is a Hemogram?

A hemogram, also known as a complete blood count, is a test that measures the number and ratio of blood cells. It determines the amount of basic blood components such as red blood cells (erythrocytes), white blood cells (leukocytes) and platelets.

Important Information: Hemogram results do not establish a diagnosis on their own. Values should be evaluated together with age, sex, medications used, existing diseases and laboratory reference ranges.

Why Is a Hemogram Test Performed?

The hemogram test is a test that provides comprehensive information about your health and plays an important role in the early diagnosis of many diseases. Having it done as part of routine check-ups is of great importance for protecting your health.

The hemogram test;

It is used to detect anemia, which is a deficiency of red blood cells; to show the presence of an infection in the body due to an increase or decrease in the number of white blood cells; and to detect bleeding disorders. The hemogram test is performed as part of the evaluation of immune system disorders and routine health check-ups.

In addition, hemogram testing is performed regularly for the follow-up of blood diseases such as leukemia and lymphoma. This is important for monitoring the course of the disease and evaluating the response to treatment.

Hemogram Test Parameters and Grouping:

  1. Red Blood Cells (Erythrocytes): RBC, Hemoglobin (Hgb or Hb), HCT, MCV, MCH, MCHC, RDW.
  2. White Blood Cells (Leukocytes): WBC, differential leukocyte count. (Neutrophils, lymphocytes, monocytes, eosinophils and basophils are subparameters.)
  3. Platelets: PLT, MPV, PDW.

Do Not Postpone Your Hemogram Results

If your hemogram values are high or low, or if there is a suspicion of anemia, infection or a bleeding disorder, you can get an evaluation from internal medicine specialists.

What Are the Normal Reference Values for a Hemogram?

Hemogram test results are usually evaluated within certain reference ranges. These ranges may vary according to age, sex and the laboratory. By measuring the number and ratio of various blood cells, it provides information about health status.

What Are the Hemogram Test Parameters and What Do They Mean?

  • WBC (White Blood Cell Count): It determines the number of white blood cells. White blood cells protect the body against infections.

    When a high value is found, infectious diseases and inflammation, allergic diseases, rheumatic diseases, bone marrow diseases and tumors come to mind. If the WBC value is low, it indicates radiotherapy, bone marrow diseases, malnutrition or vitamin deficiency.

  • RBC (Red Blood Cell Count): It determines the number of red blood cells. Red blood cells carry oxygen from the lungs to other parts of the body.

    The RBC value decreases in conditions such as leukemia, cancer, anemia and pregnancy. The RBC value increases with smoking, alcohol and stimulant substance use, and in heart diseases.

  • Hemoglobin (HGB or HB): It measures the amount of the oxygen-carrying protein found in red blood cells.

    Hemoglobin increases in conditions such as lung diseases, excessive vomiting and fever. Hemoglobin decreases in conditions such as cirrhosis, anemia and chronic kidney diseases.

  • HCT (Hematocrit): It determines the ratio of red blood cells to the total blood volume.

    Low HCT value: iron deficiency anemia, enlarged spleen, blood cancer, kidney diseases, pregnancy, folic acid, vitamin B6 and vitamin B12 deficiencies cause hematocrit value to decrease. High HCT value; in cardiovascular diseases and when the body is dehydrated, the HCT value increases.

  • MCV (Mean Corpuscular Volume): It measures the average volume of red blood cells (erythrocyte volume).

    The MCV value decreases in conditions such as iron deficiency anemia, blood loss, thalassemia and copper deficiency. The MCV value increases in folic acid deficiency, vitamin B12 deficiency, hypothyroidism and liver failure.

  • MCH (Mean Corpuscular Hemoglobin): It determines the average amount of hemoglobin in a red blood cell.

    When it is low, conditions such as iron deficiency, anemias and chronic diseases occur. When it is high, vitamin B12 deficiency and folic acid deficiency are considered.

  • MCHC (Mean Corpuscular Hemoglobin Concentration): It measures the average hemoglobin concentration of red blood cells. This parameter is used to distinguish types of anemia.
  • PLT (Platelet Count): It determines the number of platelets. Platelets enable blood clotting and stop bleeding.

    The PLT value is high in allergic diseases, some types of cancer and infections. Low PLT; in severe anemia, vitamin B12 deficiency, cirrhosis, leukemia and vitamin deficiency, the PLT value is low.

  • RDW (Red Cell Distribution Width): It evaluates the variability in the sizes of red blood cells.

    The RDW value increases due to reasons such as vitamin B12 deficiency, iron deficiency and folate deficiency.

  • MON (Monocytes): They are a type of white blood cell and play an important role in immune system functions.

    A high monocyte level indicates health problems such as infection, inflammation or cancer in the body. A low monocyte level brings bone marrow diseases to mind.

  • BASO (Basophil): It refers to the amount of basophils, a type of white blood cell.

    Allergic reactions, chronic inflammation, infections and some types of cancer (especially leukemia) may cause basophil levels to increase.

  • EOS (Eosinophil): It is a type of white blood cell and plays an important role in immune system functions.

    A high EOS level may indicate health problems such as allergic diseases, poisoning, parasitic diseases, medication use and gastritis.

  • MPV (Mean Platelet Volume): It refers to the average volume of platelets.
  • LYM (Lymphocyte): Lymphocytes are important components of the immune system and protect the body against infections.
  • PDW (Platelet Distribution Width): It shows the variation in platelet sizes.
  • NEUT (Neutrophil): The NEUT value refers to the ratio of neutrophils to total white blood cells.

    Bacterial infections, inflammatory diseases, stress, corticosteroid use and some types of cancer increase the NEUT value. Viral infections, chemotherapy, radiotherapy and some autoimmune diseases decrease the NEUT value.

    The hemogram test is a test that provides comprehensive information about your health and plays an important role in the early diagnosis of many diseases. Having it done as part of routine check-ups is important for protecting your health.

Frequently Asked Questions

What does a hemogram test show?
A hemogram shows the number and ratio of basic blood components such as red blood cells, white blood cells and platelets.
Why is a hemogram test performed?
A hemogram test may be performed to detect anemia, infection, bleeding disorders and immune system disorders, and to monitor some blood diseases.
Are hemogram values the same for everyone?
Hemogram test results are evaluated within reference ranges that may vary according to age, sex and the laboratory.
What can a high WBC value mean?
A high WBC value may suggest conditions such as infections, inflammation, allergic diseases, rheumatic diseases, bone marrow diseases and tumors.
What does low hemoglobin suggest?
Low hemoglobin may be seen in conditions such as anemia, cirrhosis and chronic kidney diseases. The result should be evaluated together with the clinical condition.
Can a hemogram result alone make a diagnosis?
A hemogram test provides important information about health status; however, results should be evaluated together with examination findings, symptoms and additional tests when needed.

References

Academic Hospital note: If your hemogram results include values outside the reference range, or if you have symptoms such as fatigue, signs of infection, bleeding, bruising, palpitations or shortness of breath, you can book an appointment for specialist evaluation