PMLSP-2-LEC_REVIEWER_2ND-SEM.-PRELIMS

Principles of Medical Laboratory Practice 2 (Lecture) - 2nd Sem. Prelims Coverage

Understanding Phlebotomy

• Phlebotomy Definition & History

  • Derived from "Phleb" (vein) and "Otomy" (incision) – meaning cutting a vein.

  • Historical context: Act of bloodletting as a therapeutic practice.

• Phlebotomy Methods

  • Venesection: Surgical removal of blood from a vein to treat conditions like fever or to induce fainting.

  • Cupping: A technique using suction to draw blood to the skin surface, followed by small incisions to remove it.

• Evolution of Phlebotomy

  • Leeches: Historically used to alleviate pain or pressure by removing blood.

  • Therapeutic Phlebotomy: Applied to conditions like polycythemia vera (excess RBCs) and hereditary hemochromatosis (iron overload); typically about 500 mL blood is drawn for treatment.

  • Diagnostic Phlebotomy: Focused on blood collection for laboratory testing, moving away from treatment applications.

Phlebotomy Techniques

• Venipuncture: Blood collection from a vein.

• Capillary Collection: Small sample collection via fingerstick or heelstick.

Role of a Phlebotomist

1. Primary Duty: Blood collection.

2. Other Responsibilities:

   • Patient care

   • Sample processing

   • Receptionist tasks

   • Computer work

   • Representing the lab during patient interactions.

3. Pre-analytical Phase (Pre-examination): Ensuring accurate blood collection for diagnosis.

Types of Laboratories

Traits of a Professional Phlebotomist

• Education & Certification

  • ASCP Certification: Required in specific states (USA).

  • State License Categories:

    • Limited Phlebotomy Technician: 25 skin punctures.

    • Phlebotomy Technician I: 50 venipunctures, 10 skin punctures, certification, and passing an exam.

    • Phlebotomy Technician II: Technician I + 20 arterial punctures.

• Professionalism

  • Maintain a clean and neat appearance.

  • Display a calm and compassionate demeanor.

  • Avoid rushed actions.

• Dress Code

  • No visible tattoos or piercings.

  • Fingernails ≤ ¼ inch.

  • Uniforms: Scrub suits are mandatory, casual attire is not allowed, including open-toed shoes and T-shirts.

Healthcare Professionals in the Lab

1. Phlebotomist → Lab Assistant → Medical Laboratory Technician (MLT)

2. Histologic Technician: Requires a degree + 1 year in histopathology; must pass a certification exam.

3. Cytotechnologist: Requires a degree + 12 months accredited training; certification exam is necessary.

4. Medical Laboratory Scientist (MLS/CLS): Requires a degree + clinical training; certification is needed for supervisory/admin roles.

5. Pathologist: Physician specialized in pathology, serves as a consultant to other physicians.

Common Certifications

• Medical Technologists:

  • MLS (ASCP): Medical Laboratory Scientist (ASCP).

  • MT (AMT): Medical Technologist (AMT).

• Medical Laboratory Technicians:

  • MLT (ASCP): Medical Laboratory Technician (ASCP).

  • MLT (AMT): Medical Laboratory Technician (AMT).

• Phlebotomists:

  • PBT (ASCP): Phlebotomy Technician (ASCP).

  • RPT (AMT): Registered Phlebotomy Technician (AMT).

  • CPT (ASPT): Certified Phlebotomy Technician (ASPT).

  • CPT (NPA): Certified Phlebotomy Technician (NPA).

Communication in Healthcare

Effective Communication

1. Use both verbal and non-verbal communication effectively.

2. Show respect for diversity.

3. Exhibit professional behavior.

4. Employ a patient-centered approach.

Patient’s Bill of Rights

1. Show concern for patients, even if they are irritable.

2. Explain that tests are ordered by physicians.

3. Inform patients about procedures.

4. Respect the patient's right to refuse blood collection.

5. Keep patient information confidential.

6. Provide patients access to their medical records.

7. Expedite sample processing for timely results.

Types of Healthcare Settings

• General Departments: Administration, Laboratory, Pharmacy, Radiology, Nursing, Physical Therapy, Speech Therapy.

• Specialty Units:

  • Intensive Care (ICU, NCU)

  • Emergency Department (ED)

  • Oncology (Cancer Unit)

  • Obstetrics (Maternity Care)

  • Geriatric (Elderly Care)

Clinical Laboratory Areas

Three Phases of Sample Testing

1. Pre-examination (Pre-analytical Phase):

   • Sample collection, identification, transportation, and preparation.

   • Prevent sample contamination or clotting.

2. Examination (Analytical Phase):

   • Performing tests using machines/manual methods.

   • Ensuring proper functioning of equipment & reagents.

3. Post-examination (Post-analytical Phase):

   • Delivering results to physicians.

   • Verifying accuracy and reliability.

   • Managing follow-up tests if necessary.

Common Sample Issues

• Lipeic Sample (Milky appearance): Caused by high cholesterol or eating before collection.

• Hemolyzed Sample (Reddish): RBCs rupture due to difficult collection or mishandling.

• Normal Serum Sample: Clear with no contamination.

Laboratory Area Functions

Handling Patient Situations

1. Patient Requests Test Results: Inform them that only the physician can discuss results.

2. Patient Refuses Blood Extraction: Explain necessity and notify the nurse if refusal continues.

3. Patient Doubts the Doctor’s Request: Reassure them politely; confirm orders with the physician if necessary.

The Heart and Circulation

• Heart Overview: Muscular organ pumping blood through the circulatory system.

• Blood Vessels: Tubular structures transporting blood throughout the body.

• Septum: Divides the heart into left and right sides.

Four Heart Chambers

• Right Atrium (RA): Receives deoxygenated blood from the body.

• Right Ventricle (RV): Pumps blood to the lungs via the pulmonary artery.

• Left Atrium (LA): Receives oxygenated blood from the lungs.

• Left Ventricle (LV): Pumps oxygenated blood to the body via the aorta.

Layers of the Heart

• Endocardium: Smooth inner lining for blood flow.

• Myocardium: Middle muscular layer responsible for contraction.

• Epicardium: Outermost layer and contains pericardial fluid.

• Visceral Layer: Covers the heart's inner part.

• Parietal Layer: Outer fibrous layer protecting the heart.

Heart Valves

• Atrioventricular (AV) Valves: Prevent backflow between atria and ventricles.

  • Tricuspid Valve: Between RA and RV.

  • Bicuspid (Mitral) Valve: Between LA and LV.

Semilunar Valves

• Control blood flow from ventricles to major arteries.

  • Pulmonary Valve: Entrance of pulmonary artery (RV → lungs).

  • Aortic Valve: Entrance of aorta (LV → body).

Functions of the Heart

• Cardiac Cycle: Sequence of systole (contraction) and diastole (relaxation).

• Electrical Conduction System: Regulates heart rhythm and contractions.

• Electrocardiogram (ECG/EKG): Records the heart’s electrical activity.

• Heart sounds:

  • "Lubb": AV valves closing during ventricular contraction.

  • "Dupp": Semilunar valves closing during ventricular relaxation.

• Heart Rate: Typically 72 beats per minute.

• Cardiac Output: Volume of blood pumped per minute.

• Blood Pressure (BP): Force exerted by blood on vessel walls, measured with a sphygmomanometer.

Heart Disorders

Blood Circulation Types

• Coronary Circulation: Supplies oxygenated blood to the heart via coronary arteries.

• Pulmonary Circulation: Moves deoxygenated blood to the lungs for oxygenation and back to the heart.

• Systemic Circulation: Distributes oxygenated blood to the body and returns deoxygenated blood to the heart.

Blood Vessels

Structure of Blood Vessels

• Tunica Intima: Smooth inner layer.

• Tunica Media: Thick middle layer for contraction.

• Tunica Adventitia: Protective outer layer.

Common Veins for Phlebotomy

• Median Cubital Vein: Best site for venipuncture due to stability and size.

• Cephalic Vein: Lateral side; second-best option for venipuncture.

• Basilic Vein: Medial side; least preferred due to proximity to arteries and nerves.

Composition of Blood

Blood Cells & Functions

Red Blood Cells (Erythrocytes)

• Most numerous; produced in bone marrow; lifespan of 120 days.

White Blood Cells (Leukocytes)

• Defend against infection.

  • Types of WBCs:

    • Neutrophils: First line of defense, engulf bacteria.

    • Lymphocytes: Involved in antibody production and immune response.

    • Monocytes: Remove dead cells and debris.

    • Eosinophils: Involved in allergic reactions/parasitic infections.

    • Basophils: Release histamine for inflammation/allergic responses.

Platelets (Thrombocytes)

• Smallest component aiding in blood clotting and preventing excessive bleeding.

Blood Disorders

Blood Pressure & Measurement

• Measured: Using a sphygmomanometer.

Blood Pressure Categories

ABO Blood Group System

The Lymphatic System

Blood Clotting (Hemostasis)

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