Clinical Chemistry Overview

Purpose & Function of Laboratorians

• Assist clinicians in confirming or rejecting diagnoses.
• Provide guidelines for patient management.
• Establish prognosis for patients.
• Detect diseases through case finding or screening.
• Monitor follow-up therapy effectively.

Clinical Chemistry Overview

• Systematic study of biochemical processes related to health and disease.
• Measurement of constituents in body fluids or tissues aids in disease diagnosis.

Scope of Clinical Chemistry

• Encompasses areas such as biochemistry, pharmacology, endocrinology, and toxicology.
• Utilizes instrumentation and computer technology for biochemical analysis.

Cellular Malfunction Causes

• Trauma or invasive agent destruction.
• Genetic enzyme deficiencies.
• Insufficient essential nutrient supply.
• Lack of adequate blood or oxygen supply.
• Malignancy and waste product accumulation.
• Control system failures and defects in cellular signal recognition.

Point-of-Care Testing (POCT)

• Also referred to as near-patient, alternate-site, or patient-focused testing.
• Implemented in various settings: emergency departments, operating suites, clinics, and nursing homes.
• Addresses urgent patient care needs with portable chemistry analyzers and testing devices.

Serum Substance Categories

• Functioning Substances: Glucose, electrolytes, total protein, triglycerides, cholesterol, hormones, vitamins, and individual proteins.
• Metabolites: Urea, ammonia, creatinine, bilirubin, and uric acid as waste products.
• Damaged Cell Releases: Enzymes (e.g., LD, ALT, AST) and ferritin from cell damage or abnormal proliferation.
• Drugs and Toxins: Includes therapeutic drugs, substances of abuse, and poisons.

Laboratory Tests Types

• Chemical Tests: Direct or indirect, colorimetric, redox, and titrimetric methods.
• Enzymatic Tests: One-step or multi-step with NADH consumption measurement.
• Electrochemical Tests: Measurement of activity rather than concentration.

Lab Requests Priority

• STAT Requests: Immediate needs with turnaround time (TAT) of less than 1 hour.
• Priority Requests: Important for clinical decisions, TAT typically under 2 hours.
• Routine Requests: Non-urgent tests, generally taking 4-6 hours.

Glass and Plastic Ware Comparison

• Glassware: Breakable, reusable, excellent for acidic solutions, high thermal resistance, and low cost.
• Plasticware: Shock-proof, disposable, ideal for alkaline solutions, and flexible for cryogenic experiments.

General Types of Glass

• High Thermal Resistant Glass: Borosilicate glass, resists heat and corrosion, used for items like Pyrex and Kimax.
• Corex Glass: Six times stronger than borosilicate, good at resisting clouding and scratches, suitable for thermometers.

Purpose & Function of Laboratorians

• Assist clinicians in confirming or rejecting diagnoses.
• Provide guidelines for patient management.
• Establish prognosis for diseases.
• Detect diseases through case finding and screening.
• Monitor therapy during follow-up.

Clinical Chemistry Overview

• Involves studying biochemical processes linked to health and disease.
• Measures constituents in body fluids or tissues.
• Aims to facilitate disease diagnosis.
• Interdisciplinary scope includes biochemistry, pharmacology, endocrinology, immunology, toxicology, and analytical chemistry.

Malfunctions in Cells

• Easier to detect malfunctions than to determine specific causes.
• Malfunction factors include trauma, genetic enzyme deficiencies, nutrient shortages, inadequate blood or oxygen supply, malignancy, waste product accumulation, control system failures, and cellular recognition defects.

Point-of-Care Testing (POCT)

• Also known as near-patient or alternate-site testing.
• Utilized in emergency departments, operating suites, clinics, and nursing homes.
• Addresses acute patient needs with portable analyzers.
• Common devices: glucometers, hemoglobin meters, and coagulation testing instruments.

Serum Substances Measured

• Normal constituents: glucose, electrolytes, proteins (such as albumin and hormones), lipids (like triglycerides and cholesterol), and vitamins.
• Metabolites considered non-functional waste: urea, creatinine, bilirubin, uric acid, ammonia.

Types of Laboratory Glass

• Borosilicate Glass: Low alkali content, heat resistant, examples include Pyrex and Kimax.
• Corex: 6 times stronger than borosilicate, more resistant to scratching.
• Vycor: Used in high-temperature applications can withstand 900°C and sudden heat shocks.
• High Silica Glass: 96% silica, suitable for high precision analytical work.
• Low Actinic Glass: Amber/red-tinted to protect light-sensitive substances.
• Standard Flint Glass: Basic soda-lime glass; lower thermal resistance.

Plasticwares Overview

• Polyolefins (Polyethylene, Polypropylene): Chemically resistant to many acids, suitable for disposable wares but not as resistant in extreme conditions as other types.
• Polycarbonate Resin: Strong, glass-clear, suitable for certain laboratory applications but not with bases.
• Tygon: Flexible and nontoxic, ideal for tubing in chemical applications.
• Teflon Fluorocarbon Resins: Highly inert, suited for a wide range of temperatures and chemical exposures.

Pipets Types

• Volumetric/Transfer Pipet: Delivers fixed liquid volume for accurate measurements.
• Ostwald-Folin Pipet: Designed for viscous fluids with a blowout capability.
• Graduated/Measuring Pipets: Available in Mohr (calibrated between marks) and Serological (blown out for complete delivery).

Chemicals in Clinical Chemistry

• Analytical Grade Chemicals: High purity, labeled as Analytical Reagent (AR) or ACS, used in sophisticated analytical procedures.
• USP and NF Grade Chemicals: Not pure enough for analytical work, used in drug production.
• Primary Standards (PS): Highest purity chemicals for precise concentration measurements (99.98% pure).
• Secondary Standards: Lower purity substances compared to primary standards.

Certification and Standards

• Volumetric pipets and flasks must be certified as Class A per CAP requirements.
• IUPAC regards Grade A as atomic weight standards and Grade B as ultimate standards, contributing to the purity and quality control in laboratory protocols.