Quality Control in Clinical Laboratories: A Practical Guide

Quality control (QC) is fundamental to producing reliable and accurate laboratory results. This guide provides practical information on implementing effective QC programs in clinical laboratories.

Why Quality Control Matters

• Ensures accuracy and reliability of test results
• Detects errors before patient results are reported
• Required for laboratory accreditation
• Protects patient safety

Types of Quality Control

Internal Quality Control (IQC)

Day-to-day monitoring using control materials:

• Run controls with patient samples
• Multiple levels (normal and abnormal)
• Levey-Jennings charts for monitoring
• Westgard rules for result evaluation

External Quality Assessment (EQA)

Proficiency testing programs:

• Comparison with other laboratories
• Identifies systematic errors
• Required for accreditation

Implementing QC

1. Select appropriate control materials
2. Establish control ranges
3. Define acceptance criteria
4. Document all QC activities
5. Train staff on QC procedures
6. Review and act on QC data

Common QC Problems

• Shift: Sudden, sustained change in mean
• Trend: Gradual, progressive change
• Random error: Inconsistent, unpredictable variation

Science Logistics Limited supplies quality control materials for clinical chemistry, hematology, and other disciplines. Contact us for product information.