Comparison of capillary and venous blood samples on Swelab Alfa Plus hematology analyzer

As a finger-stick is largely painless, the micro-pipette adaptor (MPA) method is well-suited to take and analyze blood samples from children and other patients. For blood banks, MPA is an excellent tool for making fast pre-donation blood cell determinations. The method also saves the vein for donation. Here, we summarize the outcome of internal and external evaluations to demonstrate equivalency of results, within defined limits, on the Swelab Alfa Plus system (analyzer and reagents, set-up with Boule Cal) for samples collected by venipuncture and capillary collection methods.

Introduction

Swelab Alfa Plus hematology analyzer is trusted for its high reliability and ease-of-use.

From doctors’ offices and small labs to medium-sized clinical units, the system delivers 22 parameters, 3-part complete blood counts (CBC) with outstanding speed and precision.

Most importantly, Swelab Alfa Plus analyzer offers a wide choice of sampling inlets: open tube, pre-dilute, cap-piercing, auto sampler, and MPA. The MPA method—based on a simple finger-stick sample taken direct from the patient—is widely used with the Swelab Alfa Plus hematology analyzer today. This work compares the results from samples collected by the capillary methods for analysis using MPA with samples collected by venipuncture.

Materials and methods

The following material was used in this study:

  • Swelab Alfa Plus Hematology Analyzer
  • Swelab AlfaDiluent
  • Swelab AlfaLyse
  • Boule Con-Diff Low
  • Boule Con-Diff Normal
  • Boule Con-Diff High
  • Boule Cal
  • Boule MPA Micro Pipettes Plastic, EDTA

In this study, results obtained for capillary blood samples collected in Boule micro-pipettes as well as micro-collection tubes were compared to results for venous blood samples. A total of 52 donors were included (one donor was excluded from the micro-collection tube part due to too small volume). From each donor, venous and capillary K2EDTA anticoagulated whole blood samples were collected by venipuncture and finger stick, respectively. All samples were analyzed in single assays to obtain CBC and white blood cell (WBC) differential results using the OT sampling method for both the venous and capillary samples.

Parameter mean value bias was determined using venous whole blood as reference for the following comparisons:

1) Capillary blood in micropipette (MPA) with venous blood (OT)

2) Capillary blood in micro-collection tubes (OT) with venous blood (OT)

Results were compared to pre-defined acceptance criteria.

The following standards and guidelines were followed for design and implementation of the studies:

  • CLSI H26-A2. Validation, Verification, and Quality Assurance of Automated Hematology Analyzers; Approved Standard – Second Edition; 2010.
  • CLSI GP41-A6. Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; Approved Standard – Sixth Edition; 2007.
  • GP42-A6. Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard – Sixth Edition; 2008.
Results

The outcome of the comparative studies for capillary versus venous blood are presented separately in Tables 1 and 2.

table-1-1

Table 1. Comparison of capillary blood collected in micropipettes (MPA mode) versus venous blood (OT mode) NA = not applicable

table-2-1

Table 2. Comparison of capillary blood collected in bullet tube (OT mode) versus venous blood (OT mode) NA = not applicable

Conclusion

Analysis of the data demonstrates that the Swelab Alfa Plus System meets performance specifications and provides comparable results for samples collected by venipuncture and capillary collection methods.

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