What are the procedural steps for a Full Blood Count (FBC)?

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Procedural Steps for Full Blood Count (FBC)

The standardized procedure for obtaining a Full Blood Count (FBC) requires proper venipuncture technique, appropriate sample collection tubes, and specific handling protocols to ensure accurate results. 1

Patient Preparation and Equipment

  • Verify patient identity using at least two identifiers and ensure proper labeling of collection tubes to prevent sample mix-up 2
  • Select appropriate blood collection tubes (typically EDTA tubes for FBC) 2
  • Prepare necessary equipment including:
    • 19-21 gauge needles (needle size does not affect test results) 2
    • Antiseptic solution (chlorhexidine-alcohol preferred) 2
    • Tourniquet, gloves, and collection tubes 2
  • Apply personal protective equipment (PPE) to minimize infection risk 2

Venipuncture Procedure

  • Apply tourniquet for no more than 60 seconds to locate a suitable vein (prolonged application may affect results) 2
  • Perform proper hand hygiene before beginning the procedure 2
  • Clean the venipuncture site with chlorhexidine-alcohol using a scrubbing motion and allow to dry completely 2
  • Use sterile technique throughout the procedure (sterile gloves can reduce contamination rates by 43-90%) 2
  • Insert needle at appropriate angle into the selected vein 2
  • Collect blood directly into the appropriate tube, filling until vacuum is exhausted 2

Sample Handling

  • Immediately after collection, gently invert the EDTA tube 5-10 times to ensure proper mixing with anticoagulant 2
  • Avoid vigorous shaking which may cause hemolysis 2
  • Process samples as quickly as possible, ideally within 1 hour of collection 2
  • If immediate processing is not possible, store whole blood samples at room temperature (not refrigerated) 2
  • Transport samples by hand carrier rather than pneumatic tube systems, as pneumatic transport can significantly alter blood cell parameters 2

Laboratory Processing

  • Perform automated analysis using calibrated hematology analyzers 1
  • Ensure quality control measures are in place with analyzers achieving at least 90% lymphocyte purity within the lymphocyte gate 1
  • For abnormal results, prepare blood smears for manual review 2
  • Calculate absolute values for cell populations when reporting results 1

Result Reporting

  • Report results with corresponding reference ranges, which may vary by laboratory, age, and sex 1
  • Include both percentages and absolute counts when available 1
  • Ensure proper documentation of any pre-analytical variables that might affect interpretation 1

Quality Assurance Considerations

  • Trained phlebotomists consistently achieve lower blood contamination rates compared to other healthcare providers 2
  • Proper labeling and patient identification are critical to prevent errors 2
  • Hemolysis is the primary cause of unusable specimens and should be documented using a standardized scale 2
  • Provide relevant clinical information with the request to aid in appropriate interpretation 3

By following these standardized steps, healthcare providers can ensure accurate and reliable FBC results that properly inform clinical decision-making.

References

Guideline

Interpretation and Reporting of Complete Blood Cell Count (CBC) Results

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Interpretation of the full blood count in systemic disease--a guide for the physician.

The journal of the Royal College of Physicians of Edinburgh, 2014

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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