Interpretation of results - CBC and Differential counts

Overview

Interpretation of the results play an important role in the identification of the diseased condition. if the results are not interpreted properly then the diagnosis and the treatment of the disease becomes difficult.

Interpretation of Haemoglobin

When the haemoglobin value is less than the normal range, it indicates anaemia. This condition is characterised by tiredness. Besides this haemoglobin values can be lower during pregnancy; the lower limit for haemoglobin during this period is 10 g/dL, considering the increase in plasma volume during this period. The severity of anaemia can be identified by the haemoglobin values.

In men, if the values are between 11 and 12.9 g/dL, it indicates mild anaemia, if it is between 8 and 10.9 g/dL, then moderate anaemia; and if it is less than 8 g/dL, it indicates severe anaemia.
In women, a value between 11 and 11.9 g/dL indicates mild anaemia; if it is between 8 and 10.9 g/dL, then it indicates moderate anaemia; and if it is less than 8 g/dL, it indicates severe anaemia.
In pregnant women, a value between 10 and 10.9 g/dL indicates mild anaemia; if it is between 7 and 9.9 g/dL, then it indicates moderate anaemia; and if it is less than 7 g/dL, it indicates severe anaemia.

Erythrocytosis is defined as the condition where the haemoglobin value is high . This usually occur due to dehydration or increased production of red blood cells. The increased production of RBC can be due to the increased production of myeloid cells that are produced in the bone marrow during the process called haematopoiesis. These myeloid cells further differentiate into RBC, lymphocytes, granulocytes, e.t.c., Hematopoiesis is the process of producing blood cells. Four main causes of increased myeloid production are

Chronic myeloid leukaemia
Polycythemia vera
Essential thrombocythemia
Primary myelofibrosis

These are essentially cancer conditions. Furthermore he secondary causes of erythrocytosis are congenital heart disease, kidney disease, high altitude, smoking, respiratory disease, and also some tumours that release erythropoietin. RBC production.

Interpretation of Hematocrit

Lower levels of hematocrit indicate anaemia, and higher levels are indicative of increased RBC production or an increase in plasma volume.

Interpretation of Red blood cells

Red blood cell values do not have any direct indication of any health conditions. However they are necessary for calculating the RBC indices, which are important for evaluating anaemia.

Interpretation of Red blood cell indices

Red cell distribution width (RWD)

The disease known as anisocytosis is characterised by variations in red blood cell size. A higher degree of variation is indicated if the values are higher. The reason for anaemia can be determined with the aid of RWD values and MCV.

Mean corpuscular volume (MCV)

Based on the values of MCV anaemia, is grouped into three

Microcytic: Microcytic anaemia is a condition where the MCV levels are below the normal range. In this case, if RDW is normal, then , consequently, anaemia can be attributed to thalassemia, anaemia caused by chronic disease, or alternatively lead poisoning. If ,on the other hand, the RDW is high, then anaemia is due to iron deficiency, fragmentation of RBC, or sideroblastic anaemia.
Normocytic: When MCV levels are normal during anemia then it is normolytic anemia . If this combined with normal RWD, then the reasons for anaemia can be chronic diseases, acute haemorrhage, hereditary spherocytosis, a chronic liver condition, or lymphatic or myelocytic leukaemia. If normocytic anemia is combined with elevated RWD values, then the reasons for anaemia are early iron or folate deficiency, sideroblastic anaemia, sickle cell anaemia, mixed deficiency,and myelofibrosis.
Macrocytic: in this condition, the MCV levels are high. This condition, along with normal RWD, is the cause of aplastic anaemia, anaemia caused by chronic liver disease ,hypothyroidism, myelodysplastic syndrome, and alcohol use. If this condition is associated with increased RWD, then anaemia can be due to deficiency of folate or B12, myelodysplastic syndrome, cold agglutination, or immune hemolytic anaemia.

The elevated MCV in certain conditions may be due to:

Agglutination of RBCs
hyperglycemia, as this causes the RBC to swell.
Hyperleukocytosis is a condition where the large WBC are counted as an RBC.

Mean corpuscular haemoglobin

MCH correlates with MCV and helps to evaluate anaemia.

Mean corpuscular haemoglobin concentration

Based on the MCHC values, anaemia can be of two types:

Hypochromic anaemia: In Hypochromic anaemia the MCHC values are low; moreover, this condition occurs mainly due to decreased haemoglobin production. Other causes are copper and pyridoxine deficiency and lead poisoning.
Hyperchromic anaemia: In hyperchromic anaemia the MCHC values are high. Can be a result of spherocytosis, xerocytosis, and haemoglobinopathies. All these are abnormalities in the structure of the RBC.

Interpretation of White blood cells

Leukopenia

Leukopenia is the decrease in the WBC counts. The cause of this could be a decrease in WBC production, an increase in WBC utilization to fight against disease, or an excessive destruction of WBCs.

Leukocytosis

Leukocytosis is the increase in the WBC count. Generally results from an excessive production of WBC . It usually happens in inflammatory conditions and myeloproliferative diseases. Other factors that can contribute to leukocytosis include the misinterpretation of nucleated RBC as WBC, the inclusion of platelet aggregates in WBC count, and the inclusion of fibrin clumps in WBC count.

Interpretation of WBC differential Count

Once a healthcare professional notes an abnormality in the WBC counts, they perform differential counts of WBC to identify which cell type caused the abnormal condition.

Neutrophils

Neutrophila is a condition where neutrophils counts are high. Neutrophila can result from

Infection.
Trauma.
Necrosis of tissue.
Stress.
Smoking.
Myeloproliferative conditions.
Chronic inflammatory diseases.
Chronic hepatitis.
Congenital condition.
Pregnancy.
Blood loss.
Hemolytic anaemia.
Some medicines.
Obesity.
Ketoacidosis caused by diabetics.

Neutropenia is a condition where the numbers of neutrophils are less in the blood. ‘[Neutropenia can be caused by

Bone marrow failure
Megaloblastic anaemia
Heredity
Infections
Hemodialysis
Autoimmune disease
Drugs or medications

Lymphocytes

Lymphocytosis is an increase in the number of lymphocytes. And a decrease in the lymphocytes is called lymphocytopenia.

Lymphocytosis can result from:

Viral infection
Toxoplasma
Tuberculosis
Pertussis
Bruecellosis
Lymphoproliferative diseases

Lymphocytopenia can result from:

Viral infection
Autoimmune diseases
Bacterial infection
Malignant cancer
Myeloproliferative diseases
Lymphoproliferative diseases
Primary immunodeficiency diseases
medicines

Monocytes

Monocytosis is an increase in the number of monocytes. it can be due to

Infections
Endocarditis
Granulomatous diseases
Autoimmune diseases
Malignant cancer
Hemolytic disease
Cigarette smoking
Lymphoproliferative diseases

Monocytopenia is a condition where there is a decrease in the number of monocytes. It can be due to

Infection
Autoimmune disease
Hairy cell leukaemia
Aplastic anaemia
Medicines

Eosinophils

Eosinophilia is an increase in eosinophil counts. It can be due to

Hypersensitivity reactions
Lymphoproliferative diseases
Parasitic infections
Malignant cancer
Myeloproliferative diseases
Connective tissue diseases
Ectopic disease
Skin diseases
Loeffler syndrome
Medicines

Eosinopenia is a decrease in the eosinophil counts. It can be due to

Stress
Inflammation
Use of glucocorticosteroids

Basophils

Basophilia is the term for a rise in the basophil count. It can be due to

Allergy
Anaphylaxis
Malignancy
Lymphoproliferative disease
Myeloproliferative disease
Viral infection
Chronic inflammatory disease

Basopenia is a decrease in the basophil count. It can be due to

Acute infection
Hyperthyroidism
Ovulation
Medicines

Interpretation of Platelets

When platelets decrease, we refer to it as thrombocytopenia. Furthermore, clumping of platelets in the presence of EDTA can cause a decrease in the platelet count. In these instances, it is advisable to conduct repeated sampling using various anticoagulants. Additionally , platelet count less than 150,000/µL, may result from elevated sequestration in the spleen, increased peripheral utilisation, or decreased production. And, major bleeding can cause the platelet count to fall below 50,000/µL. In fact, significant bleeding may occur on its own when the count is 20,000/µL or lower. Consequently, when the count is less than 10,000/µL, then there is a risk of cerebral bleeding.

Thrombocytosis is an increase in the platelet count. In general asymptomatic thrombocytosis occurs when the count of platelet count is above 450,000/µL . Symptoms may appear if the count increases above 1,000,000/µL. An immediate increase in the platelet count can occur especially during myeloproliferative disease or splenectomy. Due to less sequestration, or bone marrow stimulation during these conditions. Usually thrombocytosis can also be due to bacteremia, fungemia, or malaria. In these cases, the disease-causing organisms is present in the blood. They are mistakenly counted as platelets. Other tests for platelets, such as mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT), are available. But is not usually included in CBC tests.

Reference

https://www.ncbi.nlm.nih.gov/books/NBK604207/

Written by Krishnambal.S

Interpretation of results – CBC and Differential counts