2. Blood & Blood specimens

BLOOD OVERVIEW

  • Definition: Blood is a life-sustaining tissue consisting of formed elements suspended in plasma.

  • Homeostasis: Blood formation (hematopoiesis) maintains balance.

BLOOD TYPES

  • Arterial Blood: Oxygen-rich, bright red, under pressure.

  • Venous Blood: Deoxygenated, darker red, lower pressure.

BLOOD COMPOSITION

  • Volume: Average 5L in adults.

  • Components: 55% plasma (liquid) and 45% formed elements (cells).

TYPES OF BLOOD SPECIMENS

  • Whole Blood: Needs anticoagulant to remain mixed.

  • Plasma: Anticoagulated, separated from cells.

  • Serum: Clotted, collected without anticoagulant.

PLASMA

  • Composition: 91% water, 9% solutes (nutrients, proteins).

  • Functions: Transportation of gases, nutrients, waste, antibodies.

FORMED ELEMENTS

  • Erythrocytes (RBCs): Carry oxygen/carbon dioxide, lifespan ~120 days.

  • Leukocytes (WBCs): Immune defense, lifespan varies.

  • Thrombocytes (Platelets): Coagulation support, lifespan ~9-12 days.

PHLEBOTOMY EQUIPMENT

  • Essential tools: gloves, antiseptics, needles, collection tubes.

  • Needles: Vary in length/gauge; larger gauges for faster flow.

PHLEBOTOMY STEPS

  1. Greet & Identify: Introduce self, ensure patient consent.

  2. Position Patient: Correctly support patient for safety.

  3. Hand Hygiene: Clean hands before and after glove use.

  4. Apply Tourniquet: 3-4 inches above site, limit use.

  5. Site Selection: Prefer mature veins; median cubital first choice.

  6. Palpation: Firm, spongy feeling indicates vein quality.

  7. Clean Site: Use antiseptic, let dry.

  8. Assemble Equipment: Prepare all gear before the procedure.

  9. Reapply Tourniquet: If needed after assembling.

  10. Examine Needle: Inspect for flaws.

  11. Perform Venipuncture: Insert needle smoothly, monitor patient.

  12. Dispose Setup: Safely discard used materials.

  13. Label Tubes: Do this at the patient's bedside.

  14. Post-Care: Ensure minimal bleeding, thank patient.

  15. Deliver Specimens: Transport per facility protocol.

DIFFICULT VEINS

  • Use techniques (heat, gentle massage) to enhance vein visibility.

PATIENT SPECIFIC CONSIDERATIONS

  • Geriatric Patients: Sensitive to procedures; adjust techniques.

  • Pediatric Patients: Careful volume limits, use capillary puncture when suitable.

NEEDLE STICK INJURY

  • Immediate Action: Rinse under water, report, seek medical advice.