Interpreting the c.b.c differential blood film Examination(part 1)

Interpreting the c.b.c & differential blood film Examination
C.B.Cs technique & procedure.
R.B.Cs WBCs PLATELETS
RBCs INDICES:
MCV MCH MCHC RDW
WBCs Differentials
Reticulocytes
Band cells
Bleeding time clotting time prothrombin time prothrombin concentration INR
PERIPHERAL BLOOD FILM:
MICROCYTIC ANEMIA
MACROCYTIC ANEMIA
Target cells
aniso-poiklocytes
acanthocytes
schistocytes

1. InterpretATION OF the Complete Blood Count & Differential and Blood Film Examinatuion (for undergraduates 3 rd year Integrated Medicine) Compiled by Ahmed Redwan, 2021 © copyrighted Assist. Lecturer Int. Med. Depart. El- Minia University, EGYPT

2. Introduction: Blood is made of two major components; plasma and cells.  Plasma is the liquid part of the blood in which the formed cells are suspended. The plasma consists of water, plasma proteins (a few of which are serum albumin and globulin and fibrinogen), electrolytes and other constituents. Plasma makes up more than half of the total blood volume .

3. The cells are the blood components that will be discussed in this review. Cells of the blood include the erythrocytes, which are the red blood cells/ corpusles (RBC); the leukocytes, which are the WBC; and the thrombocytes, also known as platelets. Blood cells are produced in the bone marrow by a process called hematopoiesis . Red blood cell production is regulated by erythropoietin , a hormone released by the kidneys. When blood oxygen is low, erythropoietin stimulates the bone marrow to produce more RBCs. Introduction (cont.):

4. What Does the CBC Test Analyze ? The CBC tests for the amount of RBCs, hemoglobin, hematocrit, reticulocytes, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Usually, platelets will also be checked with the CBC .

5. Collection and Panels Collection and panel details are as follows: Specimen: Whole blood, usually collected by venipuncture Collection: EDTA tube (purple/lavender top; see image below) containing EDTA potassium salt additive as an anticoagulant

6. Red blood cells :  (RBCs) Red blood cells : RBCs are the number of erythrocytes in 1 cubic mm of whole blood. The RBC count will be low with iron deficiency, blood loss, hemolysis and bone marrow suppression. Increases may be found when one moves to a higher altitude or after prolonged physical exercise, and can also reflect the body’s attempt to compensate for hypoxia. Normal levels in men and women are 4.6 million-5.9 million and 4.1 million-5.4 million, respectively.

7. RBCs abnormalities Polycythemia vera , a pathologic condition which is a proliferative disease of the bone marrow, causes an increase in total RBCs as well as an elevation in white cells and platelet count. Mild polycythemia may be corrected by increasing vascular fluid volume, while more severe cases require frequent phlebotomies or even radiation or chemotherapy to suppress bone marrow production.

8. Hemoglobin : Hemoglobin is the oxygen-carrying pigment of red cells. There are millions of hemoglobin molecules in each red cell. This blood component carries oxygen from the lungs to the body tissues. Decreases in hemoglobin occur for the same reasons as decreased RBCs. Normal levels in men and women are 14-18 g/dl and 12-16 g/dl respectively .

9. Hematocrit:  The test for hematocrit measures the volume of cells as a percentage of the total volume of cells and plasma in whole blood. This percentage is usually three times greater than the hemoglobin. After hemorrhage or excessive intravenous fluid infusion, the hematocrit will be low. If the patient is dehydrated, the hematocrit will be increased. Normal levels in men and women are 42 percent-52 percent and 37 percent-47 percent respectively.

10. Reticulocytes “ Immature erythrocytes” In humans, these are erythroid cells that have just undergone extrusion of their cell nucleus. They still contain some organelles that gradually decrease in number as the cells mature. ribosomes are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the endoplasmic reticulum), hence the name reticulocytes.

11. Reticulocytes: complete arrows. RBCs: arrow heads. Note the relatively larger size of reticulocytes (~24%) And its polychromatic nature (especially clear with specific stains).

12. Reticulocyte : These are the new cells released by the bone marrow. The reticulocyte count is therefore used to assess bone marrow function and can indicate the rate and production of RBCs. Normal to slightly elevated reticulocyte counts may occur with anemia demonstrating an underproduction of red cells (such as with iron or folate deficiencies), depending on the staging of the disease. Elevated levels may indicate blood loss or hemolysis. Normal levels are 0.5 percent to 1.5 percent

13. Indices Indices measure the average characteristics of the erythrocyte. The indices usually noted include the mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), the mean corpuscular hemoglobin concentration (MCHC) and red cell distribution width (RDW). MCV : This measures the average size of the RBC and can be calculated by dividing hematocrit X10 by RBC count. Normal values are 80-100 fL .

14. Low values indicate the cells are microcytic (small cells) and are often evident with conditions such as iron deficiency, lead poisoning and the thalassemias . High values greater than 100 fL indicate macrocytic cells (large cells), and are found with such conditions as megaloblastic anemia, folate or Vitamin B12 deficiency, liver disease, post-splenectomy, chemotherapy or hypothyroidism. The MCV can be normal with a low hemoglobin if the patient is hypovolemic or has had an acute blood loss.

15. MCH : MCH is the average weight of hemoglobin per red cell. Normal level is 27 to 311 picograms ( pg ) or 28-33 pg , depending on the reference . MCHC : MCHC is the average concentration of hemoglobin per erythrocyte. Normal levels can be seen with acute blood loss, folate and Vitamin B12 deficiency; these cells will still be normochromic. Hypochromic or “pale cells” will be seen with conditions such as iron deficiency and the thalassemias . Normal levels are 32 percent-36 percent.

16. RDW : This index is a quantitative estimate of the uniformity of individual cell size. Elevated levels may indicate iron deficiency or other conditions with a wide distribution of various cell sizes. Normal levels are 11.5 percent to 14.5 percent.

17. Platelets Platelets , also known as thrombocytes, are small elements formed in the red bone marrow. They are actually fragments of megakaryocyte cytoplasm (precursor cell to the platelet.) Platelets help to control bleeding. There are two means by which platelets are able to do this: one is by forming an occlusion at small injurious openings in blood vessels; and the second by a thromboplastic function which stimulates the coagulation cascade. Both platelet number (measurable by platelet count) and platelet function (not measurable by platelet count) play a role in the effectiveness of the platelet in controlling bleeding. Note that platelet count measures only platelet number, not function.

18. In the cases of thrombocytopenia, the patient will have decreased platelets and can experience severe bleeding. Thrombocytopenia may occur for many reasons, a few of which are: aplastic anemia, in which the patient experiences loss of bone marrow function; drug-induced ; or leukemia , in which the bone marrow is replaced by malignant cells. Certain conditions also reduce platelet function .

19. Many conditions can elevate platelet number, a few of which include: essential thrombocythemia , chronic leukemia (depending on stage and therapy), post-splenectomy, iron deficiency anemia, malignancy, and chronic infection or inflammation. The reader should remember that the staging of the disease process and the therapeutic regimen can cause platelet number to fluctuate. Other conditions may enhance platelet function, a few of which are atherosclerosis, diabetes, smoking and elevated lipid and cholesterol levels. These situations can enhance the patient’s chances of developing thrombosis. The normal level of platelets is 150,000-350,000/cubic mm.

20. White Blood Cells WBCs , also known as leukocytes, are larger in size and less numerous than red cells. They develop from stem cells in the bone marrow. WBC function involves the response to an inflammatory process or injury. Normal levels of WBCs for men and women are 4,300-10,800/cubic mm. When the white count is abnormal, the differential segment can measure the percentage of the various types of white cells present. Differential counts add up to 100 percent. The differential usually includes neutrophils, bands, eosinophils , monocytes and lymphocytes .

21. Though the discussion below lists each differential cell and describes increases or decreases in percentage in response to various stimuli, the reader must also remember that most of these percentages can also fluctuate in patients with certain kinds of leukemia and other pathologic conditions . Neutrophils : The function of neutrophils is to destroy and ingest bacteria. Neutrophils arrive first at the site of inflammation; therefore their numbers will increase greatly immediately after an injury or during the inflammatory process. Their life span is approximately 10 hours, then a cycle of replenishing neutrophils must occur. Besides during inflammation, neutrophils increase with such conditions as stress, necrosis from burns and heart attack. Normal levels range from 45 percent-74 percent.

22. TLC Reference ranges for differential white blood cell counts are as follows  [1]  : Neutrophils - 2500-8000 per mm 3  (55-70%) Lymphocytes - 1400-4000 per mm 3  (20–40%) Monocytes - 100-700 per mm 3  (2–8%) Eosinophils - 50-500 per mm 3  (1–4%) Basophils - 25-100 per mm 3  (0.5-1%)

23. Bands : These are occasionally referred to as “stabs” and are immature neutrophils which are released after injury or inflammation. The presence of bands indicates that an inflammatory process is occurring. An increase in the release of immature cells is known as a “shift to the left.” In the days of written reports, lab personnel would write the bands in the left margin, hence the lasting name some sources claim, which represents an increase of bands or stabs. However , other references say the shift to the left refers to the early release of younger white cells such as bands and metamyelocytes from the bone marrow reserve into the blood stream (a shift from the right, meaning mature cells, toward the left of the maturation series, meaning less mature cells). Normal level ranges from 0 percent-4 percent.

24. Eosinophils : These are found in such areas as skin and the airway in addition to the bloodstream. They increase in number during allergic and inflammatory reactions and parasite infections. Normal blood levels range from 0 percent-7 percent. Basophils : Called basophils when found in the blood, these cells are also known as “mast” cells when found in the tissues. Tissue basophils are found in the gastrointestinal and respiratory tracts and the skin. They contain heparin and histamine and are believed to be involved in allergic and stress situations. Basophils may contribute to preventing clotting in microcirculation. Normal blood levels range from 0 percent-2 percent .

25. Monocytes : These cells arrive at the site of injury in about five hours or more . The monocytes are phagocytic cells that remove foreign materials such as injured and dead cells, microorganisms and other particles from the site of injury, particularly during viral or bacterial infections. Normal levels, which vary depending on the source, range from 2 percent-8 percent3 to 4 percent-10 percent . Lymphocytes : Lymphocytes fight viral infections; B cells and T cells are two major types. Lymphocytes have a key role in the formation of immunoglobulins (humoral immunity) and also provide cellular immunity. Normal levels range from 16 percent-45 percent.

26. Immature granulocyte (IG) Immature granulocytes (IGs) encompass immature cells of granulocytic lineages, including metamyelocytes , myelocytes , and promyelocytes , which are easily recognized morphologically and are reported by automated analyzer as IG altogether.   IG normally absent from peripheral blood. Increased IG occurs accompanied by an increase in neutrophils in the following conditions:   Bacterial infections Acute inflammatory diseases Cancer (particularly with marrow metastasis) Tissue necrosis Acute transplant rejection Surgical and orthopedic trauma Myeloproliferative diseases Steroid use Pregnancy (mainly during the third trimester)

27. Bleeding Time Process It involves cutting the underside of the subject's forearm, in an area where there is no hair or visible veins. The cut is of a standardized width and depth, and is done quickly by an automatic device . A blood pressure cuff is used above the wound, to maintain venous pressure at a specified value. The time it takes for the bleeding to stop (i.e. the time it takes for a platelet plug to form) is measured. Cessation of bleeding can be determined by blotting away the blood every several seconds until the site looks "glassy".

28. BT Interpretation Bleeding time is affected by platelet function, certain vascular disorders and von Willebrand Disease—not by other coagulation factors such as haemophilia . Diseases that cause prolonged bleeding time include thrombocytopenia, disseminated intravascular coagulation (DIC), Bernard- Soulier disease, and Glanzmann's thrombasthenia . Aspirin and other cyclooxygenase inhibitors can significantly prolong bleeding time. While warfarin and heparin have their major effects on coagulation factors, an increased bleeding time is sometimes seen with use of these medications as well . People with von Willebrand disease usually experience increased bleeding time, as von Willebrand factor is a platelet adhesion protein, but this is not considered an effective diagnostic test for this condition . It is also prolonged in hypofibrinogenemia .

29. Clotting time Clotting time is the time required for a sample of blood to coagulate in vitro under standard conditions. There are various methods for determining the clotting time, the most common being the capillary tube method. It is affected by calcium ion levels and many diseases. Normal value of clotting time is 2-8 minutes. For the measurement of clotting time by test tube method, blood is placed in a glass test tube and kept at 37° C. The required time is measured for the blood to clot .

30. There are several other methods, including testing for those on anticoagulants, such as heparin or warfarin. Activated partial thromboplastin time ( aPTT ) is used for heparin studies and the normal range is 20–36 seconds, depending upon which type of activator is used in the study . Prothrombin time (PT) is used for warfarin studies. PT time for adult males' normal range is 9.6–11.8 seconds, while adult females' normal range is 9.5–11.3 seconds . Internationalized normalized ratio (INR) is also a warfarin study, with target ranges of 2–3 for standard warfarin and 3–4.5 for high-dose warfarin .

31. The international normalized ratio (INR) recommendations below are per guidelines from the American College of Chest Physicians in   Cerebrovascular event INR target (range ): Atrial fibrillation (AF) plus ischemic stroke or transient ischemic attack (TIA): 2.5 (2.0-3.0)  [2, 3, 4, 5, 6] Venous sinus thrombosis: 2.5 (2.0-3.0) Duration of therapy: Long-term AF plus ischemic stroke or TIA: Long-term Venous sinus thrombosis: 12 months

32. Thank You تم بحمد الله