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Hematology Procedure

Standard Operating Procedure

SAMPLE DOCUMENT
Document ID: HEMA-SOP-001 | Version: 2.0 | Effective Date: January 2025 | Department: Hematology
Author: Ugochi Ndubuisi, DHSc, MLS(AMT), MB(ASCP) | Classification: Clinical Laboratory Procedure

Table of Contents

1. Purpose & Scope

This Standard Operating Procedure (SOP) establishes guidelines for performing Complete Blood Count (CBC) analysis and differential white blood cell counts using automated hematology analyzers.

Clinical Significance

The Complete Blood Count (CBC) is one of the most commonly ordered laboratory tests. It provides essential information about:

  • Red Blood Cells (RBC): Oxygen-carrying capacity, anemia detection
  • White Blood Cells (WBC): Immune function, infection, inflammation
  • Platelets: Clotting ability, bleeding disorders
  • Hemoglobin/Hematocrit: Blood oxygen levels, dehydration

Scope

This procedure applies to all CBC and differential testing performed on:

2. Principle of Testing

Automated Hematology Analysis Methods

Modern hematology analyzers use multiple technologies for comprehensive cell analysis:

Technology Parameter Measured Principle
Electrical Impedance Cell count, cell size (MCV) Cells passing through aperture disrupt electrical current
Flow Cytometry WBC differential, reticulocytes Light scatter and fluorescence patterns
Spectrophotometry Hemoglobin concentration Cyanmethemoglobin absorbance at 540nm
Optical Detection Platelet count, RBC indices Laser light scatter analysis

3. Specimen Requirements

Requirement Specification Notes
Collection Tube EDTA (Lavender top) K2EDTA or K3EDTA
Minimum Volume 2.0 mL (adult), 0.5 mL (pediatric) Fill to line on tube
Stability - Room Temp 24 hours For CBC only
Stability - Refrigerated 72 hours Differential affected after 6 hours

Specimen Rejection Criteria

  • Clotted specimens
  • Hemolyzed specimens (affects WBC, platelet counts)
  • Underfilled tubes (<75% fill volume)
  • Wrong anticoagulant (not EDTA)
  • Unlabeled or mislabeled specimens

5. Quality Control

Daily QC Requirements

QC Level Frequency Parameters Action Limits
Level 1 (Low) Every 8 hours or each shift All CBC parameters ±2 SD from target
Level 2 (Normal) Every 8 hours or each shift All CBC parameters ±2 SD from target
Level 3 (High) Every 8 hours or each shift All CBC parameters ±2 SD from target

QC Failure Protocol (Westgard Rules)

1:2s Warning Rule

Trigger: One control exceeds ±2 SD

Action: Warning only - inspect other rules before releasing results

1:3s Rejection Rule

Trigger: One control exceeds ±3 SD

Action: STOP TESTING. Do not release patient results. Begin troubleshooting.

QC Failure Corrective Actions:

  1. Verify QC material is not expired
  2. Check QC material preparation/handling
  3. Run new vial of QC material
  4. Perform background check if applicable
  5. Contact supervisor if failure persists
  6. Document all corrective actions taken

7. Critical Values

Critical Value Reporting

All critical values must be reported to the ordering provider within 30 minutes.

Parameter Low Critical High Critical Clinical Significance
WBC <2.0 x10⁹/L >30.0 x10⁹/L Infection risk / Leukemia
Hemoglobin <7.0 g/dL >20.0 g/dL Severe anemia / Polycythemia
Hematocrit <20% >60% Blood loss / Dehydration
Platelets <50 x10⁹/L >1000 x10⁹/L Bleeding risk / Thrombosis risk

Critical Value Reporting Steps:

  1. Verify result accuracy (repeat if needed)
  2. Call ordering provider or designated nurse
  3. Document name, date, time of notification
  4. Request read-back of critical value
  5. Document in LIS critical value log

8. Troubleshooting

Problem Possible Cause Corrective Action
High WBC count flags NRBC interference, clumps Review peripheral smear, correct manually
Low platelet count Platelet clumping, giant platelets Check for clumps, redraw in citrate tube
Hemolysis interference Difficult draw, improper handling Request recollection
QC out of range Reagent, calibration, temperature Follow QC failure protocol

9. References

  1. Clinical and Laboratory Standards Institute (CLSI). H26-A2: Validation, Verification, and Quality Assurance of Automated Hematology Analyzers. 2nd ed. 2010.
  2. CLSI H20-A2: Reference Leukocyte (WBC) Differential Count. 2007.
  3. CAP Laboratory Accreditation Checklist - Hematology and Coagulation. 2024.
  4. 42 CFR Part 493 - Laboratory Requirements (CLIA '88).
  5. WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. 2010.

Work Sample - Ugochi Ndubuisi Portfolio

This document demonstrates SOP development expertise for CAP/CLIA-compliant clinical laboratories.

Original document created for healthcare organization - identifying information removed.