MLT 251 - Intro Hematology OBJs

Familiarize yourself with more hematology concepts.

Describe the differences between whole blood, plasma and serum.

Whole blood is the liquid blood product containing red blood cells, white blood cells, platelets, and plasma. Plasma is the fluid component of blood that remains after cells are removed, and it contains proteins, electrolytes, and waste products. At the same time, serum is the liquid that remains after coagulation, lacking clotting factors but containing antibodies.

Recall the specimen of choice for hematology testing and provide an explanation for why it is the specimen of choice.

The specimen of choice for hematology testing is EDTA-anticoagulated whole blood, as it preserves cell morphology and prevents clotting, allowing accurate analysis of blood cell counts and characteristics.

Describe the effect on red cells when they are placed in isotonic, hypotonic, and hypertonic solutions.

Red cells maintain their shape in isotonic solutions, swell and may hemolyze in hypotonic solutions, and shrink or crenate in hypertonic solutions.

Describe how EDTA prevents clotting in a blood specimen.

EDTA (ethylenediaminetetraacetic acid) prevents clotting by chelating calcium ions in the blood, which are essential for the coagulation cascade, thus maintaining the blood in a liquid state for testing.

Recall several parameters included in a CBC.

A Complete Blood Count (CBC) includes parameters such as red blood cell count, white blood cell count, hemoglobin concentration, hematocrit, and platelet count.

Explain the difference between a WBC count and a WBC differential.

A WBC count measures the total number of white blood cells in a given volume of blood, while a WBC differential breaks down the total into the different types of white blood cells, providing a percentage of each type present.

List the two main functions of the hemoglobin molecule.

To transport oxygen and carbon dioxide in the bloodstream.

Define the term 'affinity' and describe how high and low affinity affects the release of oxygen to the tissues.

Affinity refers to the strength of binding between hemoglobin and oxygen. High affinity means hemoglobin holds onto oxygen more tightly, reducing oxygen release to tissues, while low affinity allows for easier oxygen release, facilitating delivery to tissues in need.

Describe the structure of the hemoglobin molecule to include specific details of the 'globin' and 'heme' portions.

Hemoglobin is a protein composed of four globin polypeptide chains, each associated with a heme group that contains iron. The heme groups bind oxygen, while the globin chains provide structural support and facilitate gas transport.

State the form of iron that is capable of carrying oxygen and give its valence.

Iron (II) or ferrous ion, with a valence of +2.

State the name given to hemoglobin when iron is in the ferric state and give its valence.

Methemoglobin, valence of +3

Compare and contrast the terms 'oxidation' and 'oxygenation' to include the definitions and the form of iron associated with each.

Oxidation is the process by which iron loses electrons and becomes ferric (Fe^{3+}), while oxygenation refers to iron binding with oxygen, forming a ferrous (Fe^{2+}) state.

Recall the hemoglobin reference ranges.

These are the normal values of hemoglobin concentrations in blood, typically ranging from 13.5 to 17.5 grams per deciliter for men and 12.0 to 15.5 grams per deciliter for women.

State the most common condition associated with low hemoglobin.

Anemia is often caused by iron deficiency.

List several conditions that correlate with elevated hemoglobin.

Conditions such as polycythemia vera, chronic obstructive pulmonary disease (COPD), and living at high altitudes are associated with elevated hemoglobin levels.

Define 'polycythemia' and differentiate primary from secondary causes.

Polycythemia is a condition characterized by an increased number of red blood cells in the bloodstream. Primary polycythemia, also known as polycythemia vera, is a myeloproliferative disorder arising from a mutation in bone marrow cells, whereas secondary polycythemia results from external factors that increase erythropoietin production, such as chronic hypoxia or tumors.

Explain what the term relative polycythemia means.

Relative polycythemia refers to an increase in red blood cell mass due to decreased plasma volume, often caused by dehydration or fluid loss, rather than an actual increase in red blood cell production.

List three abnormal hemoglobin pigments; explain how each is formed and the general effect on oxygen release when they are present.

Abnormal hemoglobin pigments include carboxyhemoglobin, which forms when hemoglobin binds to carbon monoxide, reducing oxygen delivery; methemoglobin, formed when iron in hemoglobin is oxidized, impairing oxygen transport; and sulfhemoglobin, produced by the reaction of hemoglobin with sulfur compounds, which also hinders oxygen release.

Explain circumstances that can lead to elevated carboxyhemoglobin levels.

Elevated carboxyhemoglobin levels occur when carbon monoxide binds to hemoglobin, typically due to exposure to smoke, combustion engines, or poorly vented heating systems. This binding reduces oxygen-carrying capacity, leading to hypoxia and impaired oxygen delivery to tissues.

List three methods of analysis for hemoglobin and state which one is the most commonly utilized in the laband in POC testing.

Common methods include colorimetric assays, electrophoresis, and high-performance liquid chromatography (HPLC), with colorimetric assays being the most commonly used in the lab and in point-of-care (POC) testing.

State the principle of the cyanmethemoglobin method for determining hemoglobin and indicate the types of hemoglobin measured by this method.

The cyanmethemoglobin method determines hemoglobin concentration by converting hemoglobin to cyanmethemoglobin in the presence of potassium cyanide. This method primarily measures oxyhemoglobin, deoxyhemoglobin, and methemoglobin.

Recall the name and composition of the reagent used in the cyanmethemoglobin method.

The reagent is potassium ferricyanide, which converts hemoglobin to cyanmethemoglobin.

Indicate the function of each component in the Drabkin’s reagent.

Drabkin's reagent contains potassium ferricyanide, which converts hemoglobin to cyanmethemoglobin; sodium bicarbonate, which maintains a stable pH; and distilled water, which serves as a solvent to dissolve the components.

State cyanmethemoglobin method interferences and limitations.

Common interferences include abnormal hemoglobins, high turbidity, and substances such as carbon monoxide or sulfhemoglobin. Limitations include the inability to measure hemoglobin in samples with these interferences accurately.

State the limiting factor of the oxyhemoglobin method used in hematology testing.

The limiting factor is the presence of abnormal hemoglobins or elevated methemoglobin levels, which can interfere with accurate measurement.

Define hematocrit and give the name commonly used for a manual hematocrit.

Hematocrit is the proportion of blood volume that is occupied by red blood cells, commonly referred to as the "packed cell volume (PCV)."

Recall the hematocrit reference ranges.

Normal hematocrit reference ranges are typically 38.3-48.6% for men and 35.5-44.9% for women, indicating the proportion of blood volume occupied by red blood cells.

State the most common condition associated with a low hematocrit.

Anemia, often due to iron deficiency or chronic disease.

List several conditions that correlate with elevated hematocrit.

Conditions that may be associated with elevated hematocrit include polycythemia vera, dehydration, chronic obstructive pulmonary disease (COPD), and high altitude.

Describe how the hematocrit is determined.

The hematocrit is determined by taking a blood sample, placing it in a centrifuge, and measuring the proportion of red blood cells compared to the total blood volume.

Compare and contrast a manual with an automated hematocrit.

A manual hematocrit is determined by centrifuging blood in capillary tubes and visually measuring the layers, while an automated hematocrit uses machines to analyze blood samples and provide rapid, precise results, often as part of a complete blood count (CBC). The manual method can introduce human error, whereas automated methods improve efficiency and accuracy.

State several technical errors during the hematocrit performance and how they affect the results.

Technical errors during hematocrit performance can include improper centrifuge speed, inadequate sample mixing, and incorrect timing. These errors can lead to falsely elevated or decreased hematocrit readings, impacting diagnosis and treatment.

Define erythrocyte sedimentation rate and recall the ESR reference range.

Erythrocyte sedimentation rate (ESR) is a blood test that measures how quickly red blood cells settle at the bottom of a test tube. The reference range is typically 0-20 mm/hr for men and 0-30 mm/hr for women.

Interpret ESR results.

ESR results indicate the rate at which red blood cells settle in a tube over one hour; elevated rates suggest inflammation or infection, while low rates may indicate normal health or specific conditions.

State the most common conditions associated with elevated sed rates.

Common conditions include infections, inflammation, autoimmune disorders, and cancers. An elevated ESR can indicate the presence of an underlying disease or an inflammatory process.

List several factors that influence the ESR determination and how they affect the results.

Factors influencing ESR include anemia, age, pregnancy, and the presence of inflammatory proteins. Higher values can result from increased fibrinogen or globulins, while lower values can occur in polycythemia or dehydration.

Recall the reference ranges for WBC, RBC and platelets.

Reference ranges for WBC are typically 4,500 to 11,000 cells per microliter, RBC ranges from 4.2 to 6.1 million cells per microliter for men and 3.9 to 5.2 million for women, and platelet counts range from 150,000 to 450,000 platelets per microliter.

Recall the appropriate number of reportable decimal places for each.

The appropriate number of reportable decimal places varies by test; typically, one decimal place is used for tests like WBC and RBC counts, while two decimal places may be used for platelet counts.

Define leukocytosis, leukopenia, thrombocytosis, thrombocytopenia and thrombocythemia.

Leukocytosis refers to an elevated white blood cell count, typically indicating infection or inflammation.

Leukopenia is a decrease in white blood cells, often signaling a weakened immune response.

Thrombocytosis indicates an increased platelet count, while thrombocytopenia points to a reduced platelet count, both of which can affect clotting.

Thrombocythemia refers to an abnormally high platelet count in the blood.

Give examples of conditions associated with elevated and decreased blood cell counts.

Conditions associated with elevated blood cell counts include infections, inflammation, and certain cancers, while conditions with decreased counts can involve aplastic anemia, bone marrow disorders, and autoimmune diseases.

Recall the 5 types of WBCs that are routinely seen in the peripheral blood and the percentage and function of each.

The five types of white blood cells (WBCs) include neutrophils (54-62%, fight infections), lymphocytes (20-40%, play a role in immune response), monocytes (2-8%, aid in phagocytosis), eosinophils (1-4%, combat parasites and allergens), and basophils (0.5-1%, release histamine in allergic reactions).

Describe the components of the Wright stain and indicate which structures will stain blue, red/orange, and purple/lilac.

The Wright stain consists of a mixture of eosin (for red/orange staining), methylene blue (for blue staining), and buffers. Eosin stains the cytoplasm of cells red/orange, methylene blue stains nucleic acids blue, and both combined create purple/lilac colors in certain cell structures.

Describe the criteria used to distinguish between each of the WBC types covered in the lesson.

The criteria used to distinguish between WBC types include size, nucleus shape, cytoplasmic characteristics, and the presence of specific granules. Each type has unique features that facilitate their identification under the microscope.

Recall the conditions that may lead to increases in each of the WBC types covered in the lesson.

Increased white blood cell counts can result from infections, inflammation, allergies, or bone marrow disorders. Each WBC type may increase under specific conditions; for example, neutrophils rise during bacterial infections, while eosinophils increase with parasitic infections or allergic reactions.

Explain the effect of platelet clumps on the automated platelet count.

Platelet clumps can lead to falsely low automated platelet counts, as the analyzer may count clumped platelets as a single unit instead of individual platelets. This can result in an inaccurate representation of a patient's platelet levels.

Recall the approximate number of platelets that will be seen per oil immersion field when counts fall into the expected reference range.

The expected number of platelets seen per oil immersion field is approximately 8 to 15.