Basic Haematology Introduction

Introduction to Haematology

• Haematology is the study of blood, composed of plasma (~55%) and the formed elements (erythrocytes, leucocytes, and platelets)
• Alterations in the formed elements are often the first sign of disease in the body
• Laboratory tests measure deviations in blood constituents from normal values

Blood Composition

• Plasma: 90-92% water, 6-7% proteins, 2-3% fats, carbohydrates, electrolytes, and gases (O2, CO2)

Anticoagulants in Haematology

• Anticoagulants prevent blood clotting and are used in haematology tests
• Characteristics of anticoagulants: do not alter cell size, do not cause haemolysis, minimize platelet aggregation, and do not disrupt staining and morphology of blood cells
• Common anticoagulants used: EDTA, sodium citrate, and heparin
• EDTA is commonly used because it does not distort blood cells
• The proper proportion of anticoagulant to whole blood is important to avoid errors in test results

Blood Collection Tubes

• Different tubes are used for different tests, each with its own additive
• Additives and their uses:
  • EDTA: haematology tests (FBC/CBC) and blood bank (crossmatch)
  • Sodium citrate: coagulation tests (PT, APTT)
  • Sodium heparin: lithium level, ammonia level, and serum lead determination
  • Lithium heparin: chemistry tests
  • Thrombin: STAT serum chemistries
  • Sodium fluoride and potassium oxalate: glucose tests
  • ACD (acid-citrate-dextrose): HLA tissue typing, paternity testing, and DNA studies

Phlebotomy

• Phlebotomy is the process of obtaining a sample of venous blood
• A phlebotomist is an individual trained to draw blood for laboratory tests or blood donations
• Equipment needed for routine venipuncture:
  • Evacuated collection tubes
  • Needles/tube holder/syringes/butterfly system
  • Tourniquet
  • Alcohol wipes
  • Gauze sponges
  • Adhesive bandages/tape
  • Gloves

Capillary Puncture

• Perform finger or heel puncture across the fingerprints
• For infants or neonates, puncture only within designated areas on the heel to avoid neurological or soft tissue damage

Order Form/Requisition

• A requisition form must accompany each sample submitted to the laboratory
• Essential elements of the requisition form:
  • Patient's name
  • Patient's ID number
  • Patient's date of birth and sex
  • Requesting physician's complete name
  • Source of specimen
  • Date and time of collection
  • Tests requested

Rejection of Unacceptable Specimen

• Reasons for rejecting a specimen:
  • Clotted specimen
  • Severely hemolyzed specimen
  • Improperly labelled or unlabelled specimen
  • Specimen too old
  • Failure to meet volume criteria
  • Improperly collected specimen
  • Leaking tube
  • Delay in transport
  • Collection of specimen in wrong tube

Safety and Infection Control

• Practice universal precautions to protect yourself and others
• Wear gloves and a lab coat or gown when handling blood/body fluids
• Change gloves after each patient or when contaminated
• Wash hands frequently
• Dispose of items in appropriate containers
• Dispose of needles immediately upon removal from the patient's vein
• Follow institution's guidelines regarding treatment and follow-up if stuck with a contaminated needle

This quiz introduces the basics of haematology, covering topics such as haematopoiesis and its regulation. It is a foundational course for students of health sciences and biomedicine.