Preparation of Internal Quality Control Material for Lymphocyte Subset Analysis

Area of Science:

• Clinical laboratory diagnostics
• Immunology
• Biotechnology

Background:

• Lymphocyte subset analysis is crucial for clinical diagnostics, requiring reliable quality control (QC) materials.
• Commercially available QC materials are often expensive and have limited shelf lives, posing challenges for resource-poor settings.

Purpose of the Study:

• To develop and validate a cost-effective method for preparing homemade internal QC materials for lymphocyte subset analysis.
• To identify optimal conditions for fixation, freezing, and cryopreservation of these homemade QC materials.

Main Methods:

• Comparison of various fixation methods (paraformaldehyde concentrations), freezing solutions (dimethylsulfoxide, BSA-PBS, ethanolic dehydration), and cryopreservation temperatures (-20°C, -80°C, -196°C).
• Evaluation of long-term stability of QC materials prepared under optimal conditions (4% PFA, 10% DMSO, -80°C) over 1-2 months.
• Lymphocyte subset analysis using BD Multitest IMK kit.

Main Results:

• Optimal preparation involved fixation with 4% paraformaldehyde (PFA), freezing with 10% dimethylsulfoxide (DMSO), and storage at -80°C.
• Homemade QC materials (QM1 and QM2) demonstrated stability for 1-2 months of cryopreservation.
• Acceptable coefficients of variation (CV <3% for CD3, CD4, CD8; 5-7% for CD16/56, CD19) were achieved.

Conclusions:

• The proposed method offers a viable, cost-effective alternative for preparing internal QC materials for lymphocyte subset analysis.
• This approach enhances the accessibility of reliable diagnostic testing in resource-limited laboratory environments.