laB 12: Blood & Bone marrow smears Prepared by: Mr:Mahmoud El-Hindi Miss:Afnan Abdelmoneim

Objectives Handling and evaluation of blood & bone marrow smears. 2. Understand methods for detection

Introduction A peripheral blood smear (or blood film):is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood films are examined in the investigation of hematological (blood) disorders and are routinely employed to look for blood parasites, such as those of malaria and filariasis.

Preparation Blood films are made by placing a drop of blood on one end of a slide. Using a spreader slide to disperse the blood over the slide's length. The aim is to get a region; called a monolayer. where the cells are spaced far enough apart to be counted and differentiated.

Cont.. The slide is left to air dry, after which the blood is fixed to the slide by immersing it briefly in methanol. The fixative is essential for good staining and presentation of cellular detail. After fixation, the slide is stained to distinguish the cells from each other.

Cont.. Wright-Giemsa combination stain is also a popular choice. These stains allow for the detection of white blood cell, red blood cell, and platelet abnormalities. Hematopathologists often use other specialized stains to aid in the differential diagnosis of blood disorders.

Cont.. After staining, the monolayer is viewed under a microscope using magnification up to 1000x. Individual cells are examined and their morphology is characterized and recorded.

There are three main cells within the blood that the test focuses on: red cells (which carry oxygen throughout the body) white cells (which function as part of the body’s immune system). platelets (which are important for blood clotting)

Cont.. Abnormalities in the shape, size, and number of the red blood cells can affect how oxygen travels throughout the blood. These abnormalities are often caused by a mineral or vitamin deficiency, but can be caused by abnormal proteins such as in sickle cell anemia.

Cont.. White blood cells are an integral part of the body’s immune system, a network of tissues and cells that function to keep the body safe from invading microorganisms and eliminate existing infection. Disorders affecting these cells can often result in the body’s inability to eliminate or control infections.

Cont.. Platelet disorders affect blood clotting and are often the result of the body producing the wrong amount of platelets needed (either too many or too few).

Overview Evaluation of complete blood count data and examination of a peripheral blood smear are the first diagnostic steps in defining a hematologic disease. The information gathered from examination of these data may dictate subsequent diagnostic tests and procedures.

Cont.. The reliability of the information obtained from the smear depends to a considerable extent on the quality of the preparation. Properly spread films are essential to accurate work. The slides must be perfectly clean and free of grease.

Disorders Characteristic red blood cell abnormalities are anemia, sickle cell anemia and spherocytosis. Sometimes the microscopic investigation of the red cells can be essential to the diagnosis of life- threatening disease (e.g. TTP). Thrombotic thrombocytopenic purpura (TTP)

Cont.. White blood cells are classified according to their propensity to stain with particular substances, the shape of the nuclei and the granular inclusions.

Blood Disorders Affecting Red Blood Cells Anemia : People with anemia have a low number of red blood cells. Mild anemia often causes no symptoms. More severe anemia can cause fatigue, pale skin, and shortness of breath with exertion

Cont.. Aplastic anemia: In people with aplastic anemia, the bone marrow does not produce enough blood cells, including red blood cells. A viral infection, drug side effect, or an autoimmune condition can cause aplastic anemia. Medications, blood transfusions, and even a bone marrow transplant, may be required to treat aplastic anemia

Cont.. Sickle cell anemia: A genetic condition that affects mostly people . In sickle cell anemia, the red blood cells are sticky and stiff. They can block blood flow. Severe pain and organ damage can occur.

Cont.. Polycythemia vera: The body produces too many blood cells, from an unknown cause. The excess red blood cells usually create no problems but may cause blood clots in some people.

Cont.. Malaria: A mosquito's bite transmits a parasite into a person's blood, where it infects red blood cells. Periodically, the red blood cells rupture, causing fever, chills, and organ damage.

Bone Marrow Aspirate Smears

Introduction Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called a trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of conditions, including leukemia, multiple myeloma, lymphoma, anemia, and pancytopenia

Cont.. The bone marrow produces the cellular elements of the blood, including platelets, red blood cells and white blood cells. While much information can be gleaned by testing the blood itself (drawn from a vein by phlebotomy), it is sometimes necessary to examine the source of the blood cells in the bone marrow to obtain more information on hematopoiesis; this is the role of bone marrow aspiration and biopsy.

Normal smear

A Wright's stained bone marrow aspirate smear of patient with precursor B-cell acute lymphoblastic leukemia.

Multiple myeloma Multiple myeloma is a malignant, clonal disorder of plasma cells that originates in the bone marrow. It’s a relatively common disorder, accounting for 1% of all malignancies and 10% of all hematologic malignancies in adults. Patients present with painful, lytic lesions of the bones, recurrent and persistent infections, weakness, renal failure, and hypercalcemia.

Cont.. Patients with myeloma have a monoclonal proliferation of plasma cells in the bone marrow, meaning that there are a ton of malignant plasma cells that all originated from the same initial cell.