Study Notes for Principles of Medical Laboratory Science

PRINCIPLES OF MEDICAL LABORATORY SCIENCE 2nd Semester A.Y. 2025-2026

PHLEBOTOMY

  • Definition:

    • The medical term "phlebotomy" is derived from the Greek words "phlebo" (blood vessels or vein) and "-tomy" (to cut into or to make an incision).

    • Modern usage refers to the process of drawing blood for medical testing.

  • Bloodletting:

    • Refers to the withdrawal of substantial amounts of blood from a patient to cure or prevent illness and disease.

EVOLUTION OF PHLEBOTOMY

  • Stone Age:

    • Utilization of crude tools to cut vessels and drain blood.

  • Ancient Egyptians (1400 B.C.):

    • Engaged in bloodletting as a medical practice.

  • Hippocrates (460 - 377 BC):

    • Advocated for the balance of the four humors, which included bloodletting to remove excess blood.

  • Middle Ages:

    • Bloodletting continued and was performed by barber-surgeons; it was believed to bleed out evil spirits.

    • Mesopotamians practiced bloodletting for both sacrificial and medical purposes.

HISTORICAL PERSPECTIVE

  • Earliest Methods:

    • Bloodletters utilized sharpened wooden sticks or stones, lacking the concept of antisepsis, leading to the transmission of infections.

  • Barber Pole Origin:

    • The striped barber pole: red symbolizes blood, and white represents clean bandages. The pole indicated the tool that patients would hold to encourage blood flow.

CHANGE IN PHLEBOTOMY’S ROLE

  • Before:

    • Bloodletting was employed as a therapeutic measure for illnesses, not as a diagnostic tool.

  • Now:

    • Blood is primarily drawn for diagnostic purposes to identify the causes of illness, not merely for treatment.

ROLE OF PHLEBOTOMIST

  • Primary Duty:

    • To collect blood specimens for laboratory analysis through venipuncture without damaging the vein.

PROFESSIONAL ETHICS

  • Hippocratic Oath (400 BC):

    • Key principles include:

    • Do no intentional harm.

    • Practice according to sound abilities and judgments.

    • Execute only trained procedures.

    • Deal only with assigned patients.

    • Keep patient information confidential.

    • Respect patient rights.

PATIENT'S RIGHTS

  • Responsibility of Health Care Members:

    • Acknowledge first responsibility to patient safety and dignity.

  • Patient’s Bill of Rights:

    • Hospitals often adopt this, developed by the American Hospital Association, to ensure:

    • Respectful care.

    • Accurate information.

    • Informed consent.

    • Right to refuse blood tests.

    • Privacy and confidentiality.

PATIENT-CLIENT INTERACTION

  • Key Points:

    • Ensure patient reassurance and effective communication.

    • Maintain positive customer relations and adapt to patient diversity.

COMMUNICATION IN HEALTHCARE

  • Types:

    • Verbal Communication.

    • Nonverbal Communication.

    • Active Listening.

CLINICAL ANALYSIS AREAS

  • Includes:

    • Hematology.

    • Coagulation.

    • Chemistry.

    • Serology.

    • Microscopy.

    • Microbiology.

    • Blood bank/immunohematology.

STAT LABS

  • Definition:

    • Established in emergency rooms for immediate testing.

  • Reference Laboratories:

    • Large independent labs that provide routine and specialized specimen analysis from numerous facilities in the area.

SAFETY IN PHLEBOTOMY

  • Definitions:

    • Infection: Occurs when microorganisms invade the body and multiply, causing injury or disease. Includes communicable and nosocomial infections, as well as healthcare-associated infections (HAIs).

    • Pathogen: A microbe like bacteria, fungi, protozoa, or viruses that can cause disease.

    • Blood-borne Pathogen: Any pathogen that can spread via blood and body fluids.

    • Biohazard: Anything potentially hazardous to humans or the environment.

TYPES OF INFECTION

  • Nosocomial Infection:

    • Healthcare-associated, develops 48 hours after admission or within 30 days after discharge.

  • Community-acquired Infection:

    • Acquired before hospital admission.

  • Local Infection:

    • Confined to one area of the body.

  • Systemic Infection:

    • Affects the entire body.

  • Autogenous Infection:

    • Originates from the patient’s own flora.

CHAIN OF INFECTION

  • Key Components:

    • Susceptible Host: Immunosuppressed, diabetic, burn patients.

    • Source: People, equipment, water.

    • Portal of Entry: Mucous membranes, gastrointestinal tract, respiratory tract, broken skin.

    • Portal of Exit: Excretions, secretions, droplets.

    • Means of Transmission: Direct contact, ingestion, fomites, air.

TRANSMISSION OF INFECTION

  • Types:

    • Direct Contact: Physical transfer of infective material.

    • Vector Transmission: Insects that transmit diseases (e.g., malaria via mosquitoes).

    • Vehicle Transmission: Transfer through contaminated items.

    • Airborne Transmission: Droplets carried in the air.

    • Droplet Transmission: Passed within 1 meter of a patient.

STANDARD PRECAUTION

  • Treat all specimens as potentially infectious and highly hazardous.

MEDICAL ASEPSIS

  • Includes practices like handwashing.

PERSONAL PROTECTIVE EQUIPMENT (PPE)

  • Definition: Equipment to protect the phlebotomist from infectious materials. Includes:

    • Masks: Prevent airborne transmission; should not be worn around the neck.

    • Goggles/Face Shields: Protect against splashing.

    • Gowns: Fluid-resistant gowns to protect clothing and skin.

    • Gloves: Prevent transmission of microbes from personnel to patients and vice versa.

PHLEBOTOMY EQUIPMENT

  • Syringe and Needles:

    • Larger syringes create more vacuum but pose risks of collapsing veins if too large.

  • Recommended Needle Length: 1 inch to 1 ½ inches; sharper bevels cause less pain.

  • Needle Gauge:

    • 27 gauge: PPD skin test

    • 25 gauge: Intramuscular injections

    • 23 gauge: Butterfly/syringe collection

    • Etc.

EVACUATED TUBE SYSTEM

  • Principle: Tubes have built-in vacuum that is replaced by blood upon puncture.

BUTTERFLY COLLECTION SYSTEM

  • Definition: Utilizes a winged infusion set for blood collection.

MICROCOLLECTION EQUIPMENT

  • Retractable Lancet:

    • Hides the blade during use; allows varying puncture depths.

    • Recommended for one-time use, disposed of in sharps containers.

MICROHEMATOCRIT CAPILLARY TUBE

  • Definition: Narrow-bore pipettes used to determine packed red cell volume from microsamples. Tubes must be filled at least two-thirds full.

TOURNIQUETS

  • Purpose: Constrict blood flow to make veins more prominent; should not be left on longer than 1 minute.

ANTICOAGULANTS

  • Definition: Chemicals in tubes that prevent blood clotting during testing.

  • Various Tube Colors and Uses:

    • Red tube: No additives; for general chemistry.

    • Lavender tube: Contains EDTA; used for CBC and blood bank.

    • Light blue tube: Contains sodium citrate; for coagulation tests.

PROPER LABELLING AND IDENTIFICATION

  • Essential for accurate patient testing results. Labels must include:

    • First and last name.

    • Identification number (e.g., date of birth).

    • Collection date/time.

    • Initials/name of phlebotomist.

VENIPUNCTURE PROCEDURE

  • Step 1: Review & Access Test Request

  • Step 2: Approach, Identify, & Prepare Patient

  • Step 3: Verify Diet Restrictions & Latex Sensitivity

  • Step 4: Sanitize Hands

  • Step 5: Position Patient, Apply Tourniquet, and Ask to Make a Fist

PHLEBOTOMY SKILLS

  • Skills Include:

    • Social skills for interacting with patients.

    • Administrative skills for proper identification and reporting.

    • Technical skills for collecting blood samples effectively.

SAMPLE REJECTION CRITERIA

  • Common Reasons for Rejection:

    • Improper test requests.

    • Inappropriate transport or timing.

    • Misidentification.

    • Insufficient specimen volume.

    • Hemolysis or contamination.

SPECIMEN QUALITY

  • Hemoconcentration: Decrease in fluid content of blood leading to increases in red blood cells concentration.

  • Hemolysis: Rupture of red blood cells releasing hemoglobin.

  • Partial Tube Fill: Leads to incorrect blood-to-additive ratio.

SPECIAL POPULATION CONSIDERATIONS

  • Pediatrics: Exclusive attention for children, limiting to superficial veins and minimizing trauma.

  • Home-care & hospice patients: Require additional consideration for comfort and bedside manner.

NON-BLOOD SPECIMEN HANDLING

  • Types of Specimens:

    • Urine, semen, sputum, fecal samples, and body fluids.

URINE SPECIMEN TYPES

  • Random Specimen: Most common urine test, collected anytime.

  • First Morning Specimen: Best for pregnancy and protein testing.

  • 24-Hour Specimen: Discard first urine, collect for the next 24 hours.

SAMPLE HANDLING REMINDERS

  • Proper labeling is critical; contaminants should be avoided.

  • Ensure urine specimens are analyzed for odor, pH, etc., and should be collected in clean and leak-proof containers.