Types of Glass and Plastic Materials

Types of Glass Materials

• Borosilicate glass (silica-containing) is resistant to heating and sterilization. It's common and is often called Pyrex.
• Aluminosilicate glass (silica-containing) is strong and resists scratching and alkali attack. A common brand is Corex.
• Soft glass (Boron-free glass) has low thermal resistance and can be used with strong acids and alkalis. It's inexpensive and often used for disposables.
• Flint glass (Soda lime glass) is the most inexpensive type. It releases alkali, which can cause errors.
• Low actinic glass is amber-colored or coated; used to hold photosensitive substances.

Types of Plastic Materials

• Teflon (polytetrafluoroethylene) has excellent temperature tolerance and chemical resistance.
• Polypropylene resists most chemicals and is used for pipet tips and test tubes.
• Polycarbonate is clear, stronger than polypropylene, and has good temperature tolerance.
• Polyethylene resists most chemicals (except concentrated acids) and is used for disposable transfer pipets.
• Polystyrene is rigid, clear, and used for test tubes.
• Polyvinyl chloride is soft, flexible, but porous and often used as tubing.

Calibration

• Gravimetric calibration uses a balance to measure the weight of distilled water a piece of glassware can hold; it's the most accurate method.
• Spectrophotometric calibration measures the absorbance of colored solutions. Potassium dichromate or para-nitrophenol are examples of colored solutions.

Semi-Automatic Micropipettes

• Air-displacement pipettes use an air cushion between the liquid and the piston. It's recommended for aqueous samples.
• Positive displacement pipettes have a piston directly touching the liquid. It's recommended for viscous or high-density samples like those taken from patients.

Centrifuges

• Horizontal/Swinging bucket centrifuges spin tubes horizontally, have lower speeds, up to 3000 RPM and have a flat, tightly packed sediment.
• Fixed-angle/angle-head centrifuges spin at higher speeds, with less heat buildup, up to 7,000-9,000 RPM (RCF). Slanted sediment is a disadvantage; not recommend for procedures where decantation is needed.
• Ultracentrifuges spin at the highest speeds, up to 100,000 RPM which are used for procedures which demand ultra-high RCF that produce higher sediment packing, and are refrigerated.
• Cytocentrifuges are used for low-speed cell counting (200-2,000 rpm), especially for CSF analysis.

Glass Pipettes

• Volumetric pipettes are the most accurate; they have only one calibration mark.
• Ostwald-Folin pipettes are used for serial dilution and measuring reagents.
• Serologic pipettes are graduated down to the tip which may be used for serial dilutions and general measuring in the lab.
• Mohr pipettes are graduated and used in measuring/delivering fractions of its capacity.
• To Contain: Holds but does not deliver the volume marked.
• Blow-out: delivers the marked volume plus amounts that may cling to the inside walls of the glass pipettes

Reagent Water Types

• Type I water is the purest, subjected to multiple purification techniques for maximum purity. Best for standards.
• Type II water is suitable for most laboratory procedures, including reagent preparation.
• Type III water is only suitable for some qualitative tests.

Biological Safety Cabinets

• Class II cabinets provide the most common level of protection for a variety of materials in the lab.
• Class III cabinets protect from exposure to potentially hazardous materials and are completely enclosed; no openings.

Chemical Storage Requirements

• Flammable liquids, mineral acids, caustics, perchloric acid, air-reactive substances, and heat-reactive substances that need refrigeration should be stored separately.

Radiation Hazard

• Non-ionizing radiation is used in various lab instruments and in disinfection like germicidal lamps, lasers, and microwave energy. It is less harmful than ionizing radiation.

Fire Hazard

• The different classes of fire hazards are outlined with examples (wood, paper, cloth, rubber; flammable liquids and gases; electrical panel, motor, wiring; Combustible metals). Each class requires different types of fire extinguishers. Proper methods for fire safety procedures, such as Rescue, Alarm, Confine, and Extinguish/Evacuate are outlined.

Specific Hazard

• Information is provided about different categories of hazards like acute toxicity, corrosivity, flammability, instability, and oxidizing properties.
• Different types of hazard symbols are shown.

Laboratory Mathematics

• Formulas are provided for calculating molarity, normality, and dilutions.
• Worked examples involving these calculations are given.

Units of Measure

• List of SI and non-SI units of measure is given, and factors/prefix values used with them.

Quality Management

• Quality Management (QM) involves quality assurance (QA) and quality control (QC).
• Quality assurance/assessment ensures quality results at pre-analytical, analytical, and post-analytical stages. QC is a component of QA.
• QC is done via Shewart Levey-Jennings charts to assess accuracy and precision.
• Westgard Rules are outlined.

Blood Collection

• Venipuncture sites, tourniquets, antiseptics, and methods are outlined, including evacuated tubes and butterfly needles.
• Capillary puncture methods are provided for infants and adults.
• Order of draw procedures are also outlined

Blood Collection and Specimen Considerations

• General precautions and techniques for venipuncture
• Venipuncture methods using needles, syringes, and butterfly/winged infusion sets.
• Evacuated tube systems for blood collection; color-coded evacuated tubes with or without additives are outlined.
• Categories of additives for various tests (including lavender for hematology, pink for crossmatching, light blue for coagulation, gray for ESR or nonprotein nitrogen analysis, green for heparin, orange for separator tubes, red/black/gold for serum separator tubes (SST), light green for plasma separator tubes (PST), and gray for fluoride/oxalate).
• Order of draw procedures using evacuated tubes are outlined.

Analytical Techniques and Instrumentation

• Types of spectrophotometry
• Components of a spectrophotometer (light source, entrance slit, monochromator, exit slit, cuvette, Photomultiplier tube, and readout)
• Beer-Lambert's Law is outlined and illustrated by a formula
• Solutions in spectrophotometry (blank, standard, control)
• Quality assurance items like wavelength accuracy, absorbance check and linearity
• Double-beam spectrophotometry (in-space, in-time)
• Fluorescence and Chemiluminescence

Solute/Solvent Measurement/Analysis

• Scintillation counting methods
• Various immunoassay techniques (MEIA, FPIA) are outlined and explained.
• Turbidimetry and Nephelometry methods
• Mass spectrometry techniques (GC/MS, HPLC-MS, Tandem MS, IDMS, MALDI TOF-MS)
• NMR spectroscopy

Point-of-Care Testing (POCT)

• Advantages, disadvantages, and examples of POCT devices
• Electrochemical techniques for determining electrolytes and blood gases (potentiometry, amperometry, polarography, and coulometry; and their clinical applications).

Chemistry of Other Substances and Poisons

• Methods of determination (screening, spectrophotometry and gas chromatography).
• Examples of illicit drugs (cocaine, amphetamines, marijuana, phencyclidine, LSD), and other substances and poisons (methanol, isopropanol, ethylene glycol, carbon monoxide, cyanide, and heavy metals).

Acid-Base Homeostasis and Blood Gases

• Buffer systems (hemoglobin, plasma proteins, phosphate, and bicarbonate).
• Henderson-Hasselbalch equation; relationship between pH, bicarbonate & pCO2.
• ABG parameters, causes and interpretation and their clinical value are reviewed.
• Acid-base disorders are reviewed and categorized with descriptions of the mechanisms of the respective disorders.

Other important chemistry topics

• A review of vitamins and respective deficiencies is outlined
• Various protein (albumin, globulins) and metabolic disorders are described
• Various clinical tests (urea and BUN, creatinine, uric acid, Ammonia, etc.,) are analyzed in methods of detection, reference values, clinical significance of abnormal/normal results, and their respective tests, and respective factors that may interfere.

Liver Function

• Functions of the liver (storage, synthetic/metabolic, detoxification, secretory and excretory functions, with respect to conjugated and unconjugated bilirubin.
• Forms of bilirubin in plasma
• Derangement of bilirubin metabolism and clinical applications are provided
• Methods of bilirubin determination using direct/indirect/total and the use of accelerator to convert bilirubin to diazo compound for the determination of total bilirubin.

Clinical Enzymology

• Classes of enzymes (oxidoreductases/dehydrogenases, transferases, hydrolases, lyases, isomerases, and ligases).
• Enzyme kinetics (Michaelis-Menten and Lineweaver-Burke equations)

Specific Enzyme Analysis

• Methods/procedures (endpoint and continuous monitoring), conditions that affect enzyme reactions (pH, temperature, cofactors, and inhibitors, including competitive, non-competitive, and uncompetitive inhibition).
• Measurement of isoenzymes.
• Clinical significance of different enzyme elevations or reductions are reviewed.

Clinical Endocrinology

• Review of various hormone classes (proteins/peptides, steroids, amines)
• Various hormone functions and clinical significance of abnormal secretion patterns are provided (hyper/hypo-secretion).
• Various specific hormone analysis information, their respective testing guidelines and reference values are also reviewed and analyzed.

Other Body Fluids/Urine Analysis

• Urine and CSF proteins, myoglobin, and cardiac troponins are extensively reviewed and analyzed with respective methods, reference ranges, and clinical significance.
• Natriuretic peptides, cystatin C, β trace protein, fibronectin, and other important protein analysis, and respective testing.
• Amyloids and Homocysteine are also analyzed and their respective tests.