Evaluation of a new PCR-based CMV assay for blood donor screening

Background

According to the German Guidelines, the use of leucocyte-depleted blood components is an effective strategy for reducing the risk of transfusion-transmitted cytomegalovirus (CMV) infections. However, there is a residual risk of transfusion-transmitted infections by non cell-associated CMV. We tested a new PCR-based CMV assay developed for high-throughput blood donor screening.

Methods

CMV detection by nucleic acid amplification testing (NAT) was performed in pools of up to 48 samples of EDTA-plasma (0.1 ml per sample). Sample preparation was performed by the PoET Instrument with the PoET CMV-Kit (GFE). Analytical limit of detection (95%) is specified with 12.5 IU/ml, while the limit of detection (LoD) in pools with 48 samples is 600 IU/ml per tested sample. For evaluation of the assay, CMV reference material (1st WHO IS for human CMV 09/162) using three different concentrations (12.5 IU/ml, 25 IU/ml and 50 IU/ml corresponding to 1-fold, 2-fold and 3-fold-LoD, respectively) was tested. In addition, samples provided for proficiency testing and samples from whole blood donations were tested in a routine-like setting.

Results

Of the CMV reference material diluted with human negative plasma, all samples (N=48) were tested positive at concentrations of 25 IU/ml and 50 IU/ml, whereas only 45 of 48 samples were tested positive at a concentration of 12.5 IU/ml. Proficiency testing samples were all correctly tested. Of the 1,138 whole blood donor samples, which were tested in a total of 24 minipools, one pool was positive with the PoET CMV assay. However, positivity of this pool could not be confirmed by repeat testing. The other 23 pools were all tested negative.

Conclusion

PoET CMV on the PoET Instrument is a new and sensitive method for CMV infectivity screening of blood donors.

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