Instrumentation Systems in Photometry

Laboratory Safety and Quality Control

• Length: Measured in meters
• Mass: Measured in kilograms
• Time: Measured in seconds
• Electric current: Measured in amperes
• Thermodynamic temperature: Measured in kelvins
• Amount of substance: Measured in moles
• Luminous intensity: Measured in candelas

Comparison of Biosafety Cabinet Characteristics

• Airflow Pattern: Varies by cabinet type, either front-in/exhaust-out or recirculation-exhaust.
• Applications: Toxic chemicals and radionuclides may require specific cabinet types.
• Toxic Chemicals and Radionuclides: Some types of cabinets are designed specifically for various chemical types.

Quality Control

• Internal laboratory quality control: Involves analyzing control samples and patient specimens to monitor accuracy and precision and detect errors.
• External laboratory quality control: Involves proficiency testing programs to ensure consistency among laboratories and prevent major discrepancies in results.

Abbreviations Nomenclature for Quality Control Evaluation Rules

• The 125, 135, and 225 rules represent acceptable variations, while exceeding these limits might indicate error or bias.
• 10x rule is not recommended due to high false alert rate.
• Other rules involve criteria such as sequential observations over time for QC sample variation.

Random and Systematic Errors

• Random errors: These errors do not follow a predictable pattern, are unpredictable, and indeterminate. They include mistakes during lab work, mislabeling of samples, pipetting errors and voltage fluctuations.
• Systematic errors: This error follows a predictable trend.They frequently affect observations consistently in one direction. They include improper calibration, reagent deterioration and changes in standard materials.

Instrumentation (Spectrophotometry)

• Light/Radiant source: Provides polychromatic light.
• Entrance slit: Minimizes stray light.
• Monochromator: Isolates specific wavelengths.
• Exit slit: Controls light beam width.
• Cuvet: Holds the sample solution.
• Photodetector: Consists of barrier layer cells, phototubes, photomultipliers, and photodiodes.
• Meter/read-out device: Displays measurements.

Chemical Methods for Glucose Measurements

• Oxidation Reduction Method:
• Alkaline Copper Reduction Method: Used to reduce cupric ions to cuprous ions.
• Folin Wu Method: A sensitive method that is not specific.
• Nelson Somogyi Method: Most commonly used chemical method.
• Neocuproine Method: Forms a yellow/orange cuprous-neocuproine complex.

Enzymatic Methods for Glucose Measurements

• Glucose Oxidase Method: Measures β-D glucose; frequently used and considered the reference method.

Instrumentation (Other)

• Wavelength: Distance between successive peaks, expressed in nanometers (nm).
• Visible spectrum: 400-700 nm.
• Ultraviolet region: <400 nm.
• Infrared region: >700 nm.
• Wavelength calibration: Used for accurate measurement in different instruments (e.g., Holmium oxide glass, didymium filter).

Quantitative Measurements

• Mass spectroscopy: Based on fragmentation and ionization of molecules using energy sources.
• Gas Chromatography-Mass Spectroscopy (GC-MS): Used for detecting non-volatile substances in body fluids as a gold standard in drug testing and a standard for tandem mass spectroscopy.
• Tandem Mass Spectroscopy (MS/MS): Can detect inborn errors of metabolism from a single blood spot.
• Turbidimetry: Measures reduction of light transmission through a suspension of particles.
• Nephelometry: Measures light scattering at an angle from a light source.
• Electrophoresis: Separates charged particles in an electric field.
• Chromatography: Separates soluble components in a solution.
• Planar chromatography (includes paper and thin-layer chromatography): Commonly used for semiquantitative drug screening.
• Column chromatography (includes gas chromatography): Useful for volatile or easily converted to volatile compounds.

Specimen Collection

• Venipuncture: Method for collecting blood.
• Arterial puncture: Method for collecting arterial blood.
• Central Venous Access Devices: Used for multiple draws of blood products, drug administration, etc., commonly in critical cases.
• Point-of-Care Testing (POCT): Performed by various providers, including lab personnel and non-lab health care workers.

Carbohydrates

• Monosaccharides: Simple sugars; examples include glucose, fructose, galactose.
• Disaccharides: Formed by combining two monosaccharides; examples include sucrose, lactose, maltose.
• Polysaccharides: Complex carbohydrates; examples include glycogen, starch.

Diabetes Mellitus

• Prevalence Rate: (adults or children)
• Classification of types, causes and incidence rates
• Testing criteria (blood or urine levels)
• Associated symptoms and complications

Carbohydrates (Continued):

• Glucose metabolism: Involves enzymatic reactions and pathways like glycolysis, gluconeogenesis, glycogenolysis, glycogenesis, lipogenesis, and lipolysis.
• Hormones regulating blood glucose levels: Insulin, glucagon, cortisol, and others are discussed and their respective roles detailed in the text.

Instrumentation (continued):

• Cuvet: Holds the sample solution.
• Photodetector: Detects and converts transmitted light into electrical energy.

Liver Function Tests

• Synthesis function: Synthesis of plasma proteins, carbohydrates, lipids, lipoproteins, clotting factors, ketone bodies, and enzymes.
• Excretory function: Removing waste products from the body, including bilirubin, cholesterol, etc., from the blood through the production and secretion of bile.
• Detoxification function: Protecting the body from potentially harmful substances.
• Storage function: Storage sites of fat-soluble and water-soluble vitamins.
• Methods to measure the severity of hepatic dysfunction include those related to total protein, albumin, bilirubin, and others.

Enzymes (General):

• They are proteins produced by living cells that act as catalysts, accelerating biochemical reactions by decreasing the activation energy.
• Measured in terms of product concentration, substrate concentration, coenzyme concentration, and altered coenzyme concentration.
• Different classes and their functions (e.g., oxidoreductases, transferases, hydrolases...)

Enzyme Measurements (Specifics):

• Alkaline Phosphatase (ALP): A useful marker for monitoring the course of patients with liver-disease treatment, as well as effects of drug therapy.
• Acid Phosphatase (ACP): Used for diagnosing and monitoring prostate cancer cases and evaluating the progression of various types of disease.
• Alanine Aminotransferase (ALT): Used in the diagnosis of liver problems, monitoring the course of liver treatment, and effects of drug therapy, mainly relating to liver injury.
• Aspartate Aminotransferase (AST): Similar function as ALT; involved in the diagnosis of liver disorders.
• Lactate Dehydrogenase (LDH): Is another liver marker that can be used to monitor different health conditions.

Proteins

• Primary structure, Secondary structure, Tertiary structure, Quaternary structure of proteins are explained in the text.
• Various protein types (e.g. Albumin, Prealbumin, Globulin (alpha, beta, gamma), Fibrinogen, Ceruloplasmin...) and various functions in health are presented.

Kidney Function Tests

• Glomerular Filtration Rate (GFR): Key test measuring kidney function, involving the measurement of clearance by using substances that are not reabsorbed or secreted in the renal tubules to evaluate an individual's renal clearance ability.
• Methods for measuring GFR (e.g., Inulin clearance, creatinine clearance).
• Various diseases like prerenal azotemia, kidney/renal azotemia, which have elevated nitrogenous wastes, are frequently detected using these tests.

Electrolytes

• Sodium, potassium, chloride, calcium, and inorganic phosphorus: Are the important electrolytes; their normal reference levels, methods to measure them, and associated diseases are shown.

Blood Gases and pH

• Bicarbonate buffer system: Most important function of the kidneys regarding homeostasis and is involved in equivalent generation of alkali.
• Major states of blood abnormalities, such as metabolic acidosis/alkalosis and respiratory acidosis/alkalosis, are shown.

Endocrinology

• Pituitary gland, adrenal cortex, thyroid hormones, reproductive hormones (estrogen, testosterone, progesterone, DHEA), and parathyroid gland hormones are explained.
• Disorders related to these hormones are described, including hyperthyroidism/hypothyroidism, hyper/hypoparathyroidism.

Therapeutic Drugs

• Various medications used to treat specific conditions (e.g. heart rhythm disturbances, manic-depression, seizures, etc.) and side effects of these medications are explained.

This quiz explores key concepts related to instrumentation systems used in photometric measurements. It covers topics such as the role of slits, stray light, monochromators, wavelength calibration, and specific materials involved in these processes. Perfect for students and professionals looking to test their knowledge in optical measurement techniques.