CLINICAL CHEMISTRY INTRODUCTION TO CLINICAL CHEMISTRY OUTLINE • Clinical Chemistry • Role of Medical Technologist in Clinical Chemistry • Scope and Overview of Clin. Chem. • Importance of Clin. Chem. and the Role of Medical Technologist in Clin. Chem. • Definition of Terms Commonly Used in Clin. Chem Legend: → (Example) INTRODUCTION TO CLINICAL CHEMISTRY CLINICAL CHEMISTRY • Area of pathology that is generally concerned with analysis of body fluids • Serum in blood • Utilized the specialty of chemistry to study stages of health and diseases • Involved in the analysis of biochemical byproducts found ion biological fluids • Components/Topics o Clinical Chemistry 1 ▪ Laboratory Mathematics ▪ Specimen Collection and Processing ▪ Quality Management - maintain quality laboratory ▪ Instrumentation - principles of instruments ▪ Carbohydrates ▪ Lipids and Lipoproteins ▪ Proteins ▪ Non-protein Nitrogenous Compounds - metabolic wastes ▪ Kidney function test ▪ Liver function test o Clinical Chemistry 2 ▪ Enzymology ▪ Electrolytes ▪ Blood gases and acid-base balance ▪ Micronutrients ▪ Tumor markers ▪ Endocrinology ▪ Therapeutic drug monitoring ▪ Toxicology • Course outcomes ROLE OF MEDICAL TECHNOLOGIST IN CLINICAL CHEMISTRY • Phlebotomist - blood collection • Processing of Sample - utilization of diverse samples in various tests and techniques • Quality Control and Quality Assurance - ensure accurate and precise results LESSON 1: SCOPE AND OVERVIEW OF CLIN. CHEM. • Clinical Chemistry is the area of pathology that is generally concerned with analysis of body fluids. • It is a science, a service and an industry. • Has the ability to facilitate the proper procedures of analytic process that yield accurate and precise information in aiding patient diagnosis and treatment. • The achievement of reliable results requires that the clinical laboratory scientist be able to correctly use basic supplies and equipment and possess an understanding of fundamental concepts critical to any analytic procedure. • It also tackles units of measure, basic laboratory supplies, and introductory laboratory mathematics, plus a brief discussion of specimen and even the collection of the specimen. LESSON 2: IMPORTANCE OF CLIN. CHEM. AND THE ROLE OF MEDICAL TECHNOLOGIST IN CLIN. CHEM. IMPORTANCE OF CLINICAL CHEMISTRY • The primary purpose of clinical chemistry laboratory is to facilitate the correct performance of analytic procedures that yield accurate and precise information, aiding patient diagnosis and treatment. • Clinical chemistry is involved in the analysis of biochemical byproducts found in biological fluids, such as serum, plasma, or urine, making purification and a known exact composition of the material almost impossible. • The laboratory plays an important role through periodic measurements of glycosylated hemoglobin and microalbumin. ROLE OF MEDICAL TECHNOLOGIST IN CLINICAL CHEMISTRY • Phlebotomist o Laboratory technicians and technologists, and other health care professionals, sometimes perform phlebotomy, some individuals called phlebotomists have been specifically trained in blood collection techniques and are employed primarily to collect blood specimens. • Processing Of Samples : o When samples arrive in the laboratory, the samples are processed. The laboratory scientist must ascertain if the sample is acceptable for further processing. Once processed, the laboratory scientist should note the presence of any serum or plasma characteristic such as hemolysis and icterus. • Medical Technologists Play A Pivotal Role On The Quality Control Of A Laboartory . o QC in the laboratory involves the systematic monitoring of analytic processes in order to detect analytic errors that occur during analysis and to ultimately pre- vent the reporting of incorrect patient test results. Monitoring of analytic methods is performed by assaying stable control materials and comparing their determined values with their expected values. LESSON 3: DEFINITION OF TERMS COMMONLY USED IN CLIN. CHEM. • Absorbance : the amount of light that is absorbed by analyte in a solution; absorbance is directly proportional to the concentration of analyte.
• Acidosis : state of decrease of basic (alkali) compounds and an accumulation of acid compounds in the blood causing a decrease in pH. • Accuracy : ability of a test to obtain the known target value for a sample; an accurate test exhibits minimal bias and imprecision. • Affinity : An attractive force between substances or particles that causes them to enter into and remain in chemical combination, for example; the binding of antibody to antigen. • Aliquot : a measured portion of a sample • Alkalosis : state of excess of basic (alkali) compounds or loss of acidic compounds in the blood causing an increase in pH. Amino acid: organic acid that is the building block for proteins. • Analyte : substance that is being measured (e.g., glucose, sodium, cholesterol). • Analytical phase : all procedures related to the testing of a sample for an analyte. • Atomic absorption : a spectrophotometric method in which the analyte is an element (e.g., Ca), and it absorbs light at a specific wavelength. Decreases in light intensity hitting a photodetector corresponds to increased analyte concentrations. • Avidity : average affinity of a mixture of antibody to their corresponding antigen. • Blank : a laboratory grade water and other reagents are set up and tested as though it was another sample. This checks for background interference from reagents and allows for correction. • Buffer : A liquid that resists change in pH (Links to an external site.) when an acid or base is added. A buffer consists of a weak acid (Links to an external site.) and its conjugate base. An example of a buffer is acetic acid and sodium acetate • Calibration : process of using calibrators (samples with known analyte concentration) to construct a calibration curve used to quantitate analyte concentration in unknown (patient) specimens. • Catalyst : substance that accelerates a chemical reaction, such as an enzyme in the body. Cation: an ion carrying a positive charge. • Cathode : A cathode is the electrode which gains electrons or is reduced. In other words, it is where reduction occurs in an electrochemical cell. • Centrifugation : is a process used to separate or concentrate materials suspended in a liquid medium by use of the centrifugal force. • Concentration : amount of analyte measured in a sample expressed quantitatively (e.g., mg/dL, mmol/L). • Control : a serum-based material with assigned target values and acceptable ranges to evaluate the accuracy and reproducibility of a diagnostic assay. • Cuvette : a reaction vessel (similar to a tube) used in photometric analyzers. • Desiccant : a drying agent or substance capable of absorbing moisture. • Desiccator : a sealed chamber in which samples can be dried in the presence of a desiccant. • Diffusion : is the movement of particles from an area of higher concentration to one of lower concentration. • Dilution : is when a solvent is added to a solution, making it less concentrated. • Dissociation : is when a chemical reaction breaks a compound into two or more parts. For example, NaCl dissociates into Na + and Cl - in water. • Effusion : is when a gas moves through an opening into a low-pressure container (e.g., is drawn by a vacuum). Effusion occurs more quickly than diffusion because additional molecules aren't in the way. • Electrolyte : An electrolyte is an ionic compound that dissolves in water to produce ions, which can conduct electricity. Strong electrolytes completely dissociate in water, while weak electrolytes only partially dissociate or break apart in water. • Enzyme : protein in the body that acts as a catalyst and converts substrate to product. • Enzymatic activity : a measure of the amount of enzyme catalytic activity found in a sample; enzyme concentration is often expressed in terms of activity instead of quantitative units. • Equilibrium : occurs in reversible reactions when the forward rate of the reaction is the same as the reverse rate of the reaction. • Exudate : fluid which has leaked out of a tissue or capillary, usually in response to inflammation or injury. • HDL (High Density Lipoprotein): A lipoprotein particle found in blood that is composed of a high proportion of protein with little triglyceride and cholesterol, and is associated with reduced risk of atherosclerosis. • HIL : hemolysis, icterus and lipemia; the most common interferents found in blood specimens. • Indicator : a chemical substance or compound having a physical property that changes abruptly, usually color, near the endpoint or equivalence point of a chemical reaction. • Immunoassay : assay that relies on an antigen-antibody reaction. Intracellular: component found inside the cell. • Ion-selective electrode (ISE): a potentiometric device used to selectively measure individual electrolytes such as Na, K and Cl. • LDL (Low Density Lipoprotein): Lipoprotein particle found in blood composed of protein, with little triglyceride and high proportion of cholesterol, and is associated with increased risk of developing atherosclerosis. • Lipemia : milky coloration of plasma caused by increased lipid accumulation, usually triglycerides. Lipids: the common analytes of cholesterol and triglycerides and related compounds such as free fatty acids and lipoproteins. • Meniscus : the curved surface of a liquid. • Metabolites : products of anabolism and catabolism; analytes created by synthesis in the body (e.g., glucose, cholesterol) or breakdown (e.g., creatinine, urea). • Method/methodology : the basic measurement principle or technique that is used in an analytical system to perform a test. • Osmotic pressure : force that moves water or another solvent across a membrane separating a solution. Usually, the movement is from the lower to the higher concentration. • Photometry : measuring light intensity at various wavelengths. Plaque: lipid deposits in arteries causing stenosis and leading to cardiovascular disease. • Plasma : the clear, yellow fluid obtained when blood is drawn into a tube containing anticoagulant; the clotting
factors have not been activated and a clot is not formed (usually a purple, green or light blue tube). • Postanalytical phase : all procedures related to specimen handling and result reporting after the analytical (testing) phase. • Preanalytical phase : all procedures related to specimen collection and handling that precede the analytical (testing) phase. • Precision : the reproducibility of a test; the ability to obtain very similar quantitative values on repeat testing of a sample. • Quality Control : use of scientific methods to maintain the most accurate data possible. Procedures performed to check against a standard, such as blanks, duplicates, and spikes. • Reagent : a chemical mixture to which a sample is added to conduct a test. • Reference interval : the expected normal concentration range for an analyte in a patient population; often varies with age, gender or other partitioning factors. • Sample : the specimen after preparation for analysis (e.g., serum or plasma after centrifugation). Serum: liquid portion of plasma that remains after clot is removed. • Sensitivity : the ability to detect small quantities of a measured component. • Solute : is the substance that gets dissolved in a solvent. Usually, it refers to a solid that is dissolved in a liquid. If you are mixing two liquids, the solute is the one that is present in a smaller amount. • Solvent : is the liquid that dissolves a solute in solution. Technically, you can dissolve gases into liquids or into other gases, too. When making a solution (Links to an external site.) where both substances are in the same phase (e.g., liquid-liquid), the solvent is the largest component of the solution. • Specimen : the type of biologic fluid in which the analyte is found (e.g., blood, urine, CSF) or the form in which the fluid is tested (e.g., serum, plasma, whole blood). • Spectrophotometry : measuring light intensity at various wavelengths. • Standard : are samples for which the analyst knows the true value before running the test. Standards can be made in-house or purchased from laboratory supply companies. Standards are often used to calibrate instruments and to evaluate the accuracy of an analysis • Titer : the amount of antibody found in a specimen as a result of exposure to an antigen; a high titer typically occurs after an immune response and the titer decreases over time after exposure to the antigen. • Toxicology : analysis of therapeutic drugs or drugs of abuse. • Traceability : anchoring the calibrators of a test method to recognized reference materials and/or reference methods to ensure accuracy of results; described by a metrological traceability chain. Urine: the aqueous waste fluid produced by the kidneys; the next most common body fluid after blood used for testing. • Turbidity : the light-scattering property associated with suspended particles in a liquid. A turbid solution appears cloudy. • •