0. INTRODUCTION TO CHEMICAL PATHOLOGY

Page 1: Introduction

• Title: Introduction to Chemical Pathology

• Instructor: Dorice Berkoh

• Department: Dept. of Basic & Applied Biology, UENR, Sunyani

Page 2: Objectives

• After this course, you should be able to:

  • Describe biochemical and pathophysiological mechanisms of disease and associated biochemical treatment principles.

  • Associate signs and symptoms with the pathophysiology of disease.

  • Understand the limitations and potentials of laboratory tests.

  • Select appropriate tests and interpret results for clinical diagnosis and treatment monitoring.

Page 3: Continued Objectives

• Further objectives include:

  • Collect appropriate specimens for laboratory investigations under correct conditions.

  • Perform specific side-room tests and accurately interpret results.

Page 4: Topics for the Semester

• Topics Covered:

  • Analytical techniques and instrumentation in the Chemical Pathology lab.

  • Automation in the clinical lab.

  • Point of Care Testing (POCT).

  • Principles of Laboratory Medicine.

  • Quality Management.

  • Water, electrolyte and acid-base balance.

  • Renal function and its disorders.

Page 5: What is Chemical Pathology?

• Alternate Names:

  • Clinical Chemistry/Biochemistry

  • Medical Biochemistry

  • Pure Blood Chemistry

  • Physiological Chemistry

Page 6: Chemical Pathology Defined

• Definition:

  • A branch of pathology that employs chemical knowledge to study disease.

• Focus:

  • Examines changes in chemical components and biomedical mechanisms during disease.

  • Studies biochemical bases of disease and applies biochemical/molecular techniques in diagnosis.

  • Analyzes abnormal metabolic processes triggering illness symptoms.

Page 7: Contribution of Chemical Pathology in Healthcare

• Key Contributions:

  • Diagnosis: Clinician's decision post-examination and investigation of patient conditions.

  • Treatment: Utilization of medicines and therapies to address diagnosed conditions.

  • Monitoring: Use of diagnostic tests to assess disease progression or response to therapy (e.g., diabetes monitoring).

Page 8: Screening and Prognosis

• Screening:

  • Identifies disease presence in healthy populations or detects diseases prior to clinical evidence (e.g., phenylketonuria).

• Prognosis:

  • Predicts disease clinical outcomes based on indicators (e.g., cholesterol levels indicating CAD risk).

Page 9: Key Terminologies

• Terminologies:

  • Disease: Abnormality in the body or failure to function properly.

  • Aetiology: Causes of the disease, which can be endogenous or exogenous.

Page 10: Signs, Symptoms, and Pathogenesis

• Definitions:

  • Signs: Observable indicators of disease (e.g., findings during examination).

  • Symptoms: Patient-reported indicators (e.g., coughing).

  • Pathogenesis: Development and progression of a disease (acute vs. chronic).

Page 11: Samples & Analytes

• Clinical Samples:

  • Materials from patients used in disease investigations.

• Analytes:

  • Substances tested within the samples using appropriate tests.

Page 12: Samples for Clinical Analysis

• Common samples include:

  • Blood (plasma or serum)

  • Urine

  • Faecal matter

  • Solid tissue samples

  • Other body fluids (CSF, gastric fluid, sweat, amniotic fluid, ascitic fluid).

Page 13: Common Tests in Chemical Pathology

• Analytes Tested:

  • Blood glucose

  • Electrolytes

  • Hormones and enzymes

  • Lipids and proteins

  • Other metabolic substances.

Page 14: Tests and Indications

• Blood Glucose:

  • Assesses glucose utilization (e.g., diabetes).

• Electrolytes:

  • Key electrolytes (Na, K, Mg, Ca) analyzed for metabolic and renal disorders.

• Enzymes:

  • Specific enzymes released by damaged organs used for diagnosis (e.g., CK for heart damage).

Page 15: Hormones and Their Tests

• Hormones:

  • Secreted by endocrine glands; levels indicate gland activity (e.g., cortisol from adrenal gland).

• Lipids:

  • Indicative of coronary heart disease risk (e.g., triglycerides, cholesterol).

• Other Metabolic Substances:

  • Analyzed to evaluate organ function (e.g., BUN for kidney function).

Page 16: Proteins and Their Significance

• Proteins:

  • Indicate metabolic and nutritional disorders (e.g., albumin indicating liver or kidney problems).

Page 17: Common Specimen Used

• Blood:

  • Typically drawn from a prominent vein or capillary.

Page 18: Specimen Collection Considerations

• Factors Before Collecting Samples:

  • Patient's diet (e.g., calcium tests).

  • Current medication (e.g., oral contraceptives).

  • Time of day (specific analytes).

Page 19: Factors During Specimen Collection

• Collection Factors:

  • Posture: Affects protein levels (e.g., albumin).

  • Prolonged stasis (Venostasis): Can lead to falsely high analyte levels.

Page 20: Venipuncture Considerations

• Site of Venipuncture:

  • Avoid infusion sites as the fluid may not mix well with blood.

• Haemolysis:

  • Can cause release of intracellular contents (e.g., potassium).

Page 21: Proper Identification of Specimen

• Ensure proper labeling:

  • Patient name, location/ward, ID number, date/time, suspected pathology, requesting doctor's name, and specimen container details.

Page 22: Sample Collection Tube

• Use Correct Tubes:

  • Types: Fluoride oxalate, lithium heparin, EDTA, etc.

  • Importance: Sample type affects test integrity (e.g., lithium test validity).

Page 23: Blood Tube Examples

• Blood Tubes Used:

  • Grey cap: Fluoride/oxalate (for glucose).

  • Pink cap: EDTA (for whole blood component analysis).

  • Green cap: Lithium heparin (for plasma).

Page 24: Table of Blood Tubes and Preservatives

• Various types of blood tubes with eta colors and their uses:

  • Red: plain serum; Yellow: serum separator; Green: lithium heparin; Pink: EDTA; Grey: fluoride oxalate.

Page 25: Preservation of Samples

• Immediate Processing:

  • Plasma or serum should be separated within 2 hours post-collection.

  • Store samples at 4°C if not analyzed immediately.

Page 26: Blood Gas Analysis Considerations

• Temperature Control:

  • Must be kept at 4°C during transport; require ice chest for preservation.

• Protection from Light:

  • Hormonal assays and bilirubin samples need light protection.

Page 27: Urine Sample Guidelines

• Collection:

  • Use clean, sterile containers for samples.

• 24h Samples:

  • Preserve with necessary agents to prevent bacterial action.

Page 28: Changes in Blood Post-Collection

• Glycolysis in RBCs:

  • Can lead to decreased glucose levels; use fluoride tubes to prevent.

• Photo degradation:

  • Can affect bilirubin and beta-carotene levels; shield from light.

Page 29: Conclusion

• End of Lecture:

  • Thank you and see you in the next class!