FTIR spectroscopy of freeze-dried human sera as a novel approach for dengue diagnosis

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used as a diagnostic tool to identify the biochemical markers expressed differentially in dengue infected and healthy freeze-dried human blood sera. A total of 77 sera samples; 57 DENV infected and 20 healthy were processed. Multivariate data classification algorithms; principal component analysis (PCA), linear discriminant analysis (LDA), and partial least square regression (PLSR) were used for classified differentiation between selected wave number regions of FTIR spectra of both types of samples. PCA-LDA model applied on our data showed sensitivity and specificity of 89% and 95% respectively. PLSR model successfully predicted the infection signs based on biochemical changes in serum samples with an accuracy of R-2 = 0.9980. This study provides an initial insight that ATR-FTIR spectroscopy coupled with multivariate data classification algorithms can be used as an effective tool for dengue diagnosis. This is the first report of the use of freeze-dried human blood sera for FTIR analysis.