Evaluation of a multiplex ligation-dependent probe amplification assay for the detection of respiratory pathogens in oncological patients

BACKGROUND: Respiratory tract infections are widespread and may cause significant morbidity and mortality in immunosuppressed populations such as oncological patients. OBJECTIVES: The RealAccurate Respiratory RT PCR Kit covering 14 respiratory viruses was compared to the RespiFinder Smart22, a broad-spectrum multiplex ligation-dependent probe amplification (MLPA) test, targeting 22 viral and bacterial respiratory pathogens. STUDY DESIGN: After verification of its analytical performance, the clinical performance of the RespiFinder Smart22 was evaluated by re-analysis of 96 respiratory samples from oncological patients. Additionally, the time to result (TTR) of both methods was compared. RESULTS: The analytical performance of the RespiFinder Smart22 fulfilled all previously specified criteria. Concordant results in both assays were achieved in 74.0% of all clinical specimens and in 91.2% when only positive results were taken into account. The RespiFinder Smart22 yielded additional results in a total of 22 (22.9% of 96) samples due to higher test sensitivity and a broader, highly multiplexed spectrum of pathogens. The TTR of a typical routine test consisting of three samples were 206 and 356 min for the RealAccurate Respiratory RT PCR Kit and the RespiFinder Smart22, respectively. However, hands-on time was reduced by 59.0% applying the MLPA method. CONCLUSIONS: In our hands, the RespiFinder Smart22 showed excellent analytical performance while hands-on time was halved in comparison to the RT PCR method. Regarding the clinical evaluation, the MLPA method provided additional results in 22.9% (22/96) of specimens due to its comprehensive format, higher test sensitivity and the capability to detect 22 pathogens compared to 14 with the RealAccurate Respiratory RT PCR Kit.