Performance of Swelab Alfa Plus hematology analyzer in blood bank application

This work aims to evaluate that the Swelab Alfa Plus blood bank application meets the performance claims. The Swelab Alfa Plus instrument was run with associated reagents and checked with dedicated quality control material. Correlation studies with platelet (PLT) and red blood cell (RBC) concentrates were performed in collaboration with a Swedish University Hospital Blood bank against the reference instrument CA620 CellGuard. The results show good correlation between instruments, indicating the suitability of Swelab Alfa Plus for use in blood bank applications.

Introduction

The Swelab Alfa Plus system is an automated hematology analyzer intended for in vitro diagnostic testing of human blood samples, platelet, and erythrocyte concentrates under laboratory conditions. The blood bank application resides in the Swelab Alfa Plus system as a special analysis profile. The factory default blood bank profile is named PLT-C (PLT-Concentrate). This profile is pre-installed in the instrument and can be activated by the service technician upon delivery of the instrument.

In the PLT-C profile, several parameters are blocked, and no value is displayed on the screen or printed. In PAS (Print All Settings) the blocked parameters are removed, whereas RBC, PLT, MPV, WBC, PCT, PDW, P-LCC and P-LCR values are displayed and printed. Suggested normal ranges for the active parameters are preset as the default (for a PLT concentrate), but levels may be altered by the user. Two calibration factors are available when the blood bank option is activated, PLT-C and MPV-C.

In this work, the performance of the Swelab Alfa Plus blood bank application was compared with the corresponding application in CA620 CellGuard.

Materials and methods

The following materials were used in this study:

Swelab Alfa Plus (test instrument) was co-calibrated to CA620 CellGuard (reference instrument) for the correlation study. PLT and RBC concentrates used for the evaluation were taken from the normal routine production. After analysis on the reference instrument, samples were run in the open tube (OT) inlet of the Swelab Alfa Plus system. Single assays on the test and reference instruments were compared and results presented in scatter plots with the 95% confidence interval (confidence and prediction bands) of the linear regression indicated. Linearity testing was performed using a linearity kit with 10 levels, covering the range of the linearity claim in accordance with CLSI Standard EP06-A. The study was performed in accordance with the standard SS-EN 13612 for compliance with the demands in the European IVD directive (98/79/EC).

Results

Specification limits for the study are listed in Table 1. Correlation of test instrument with reference instrument for PLT and RBC concentrates are visualized in Figures 1 and 2.

Table 1. Specifications limits

Fig 1. Correlation of PLT concentrates between test system and reference system (n = 82). PLT linearity; recovered vs theoretical value.

Fig 2. Correlation of RBC concentrates between test system and reference system (n = 30). RBC linearity; recovered vs theoretical value.

Conclusion

Swelab Alfa Plus blood bank application measurement of PLT and RBC concentrations shows good correlation and linearity compared to reference methods. The results demonstrate that Swelab Alfa Plus is a useful tool for monitoring the quality in blood component processing in blood banks.

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