# Viability of ABO Blood Typing with ATR-FTIR Spectroscopy
## 3 Results and Discussion
### Principal Components Cobined with Naive Bayesian Classifier  
Taking into account the PCA and LDA results, it is very likely that the relationship of FTIR spectra with the ABO-type exists with a linear combination of several peak areas rather than the independent areas. For this reason, we tried a second NBC algorithm using as variables just the two first principal components. The whole dataset reduces its  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**NBC Classification**} & \multicolumn{4}{c}{**Random Classification**} \\ \hline  & \multicolumn{4}{c}{**Assigned Class**} & \multicolumn{4}{c}{**Assigned Class**} \\ \hline  & & A & B & AB & 0 & & A & B & AB & 0 \\ \cline{2-10}  & A & 9\% & 5\% & 1\% & 2\% & & A & 5\% & 8\% & 3\% & 6\% \\ \cline{2-10}  & B & 8\% & 29\% & 4\% & 1\% & & B & 8\% & 15\% & 5\% & 10\% \\ \cline{2-10}  & AB & 4\% & 8\% & 6\% & 2\% & & AB & 3\% & 5\% & 2\% & 3\% \\ \cline{2-10}  & 0 & 11\% & 8\% & 3\% & 3\% & & 0 & 6\% & 10\% & 3\% & 7\% \\ \hline  & & & & & T+ & & T- & F+ & & F- \\ \hline  & A-type success rate & \(\downarrow\) 8.6\% & \(\uparrow\) 62.1\% & \(\downarrow\) 22.2\% & \(\uparrow\) 7.1\% & & \(\downarrow\) 26.4\% \\ \hline  & B-type success rate & \(\searrow\) 29.3\% & \(\
earrow\) 38.4\% & \(\downarrow\) 19.7\% & \(\
earrow\) 12.6\% \\ \hline  & AB-type success rate & \(\downarrow\) 6.1\% & \(\uparrow\) 73.7\% & \(\uparrow\) 7.6\% & \(\
earrow\) 12.6\% \\ \hline  & 0-type success rate & \(\downarrow\) 2.5\% & \(\uparrow\) 72.2\% & \(\uparrow\) 4.0\% & \(\downarrow\) 21.2\% \\ \cline{2-10}  & NBC Success rate & \(\downarrow\) 11.6\% & \(\uparrow\) 61.6\% & \(\searrow\) 13.4\% & \(\searrow\) 13.4\% \\ \hline  & \multicolumn{4}{c}{NBC classification} & \multicolumn{4}{c}{Random classification} \\ \hline  & \multicolumn{4}{c}{Assigned class} & \multicolumn{4}{c}{Assigned class} \\ \hline  & & A & B & 0 & & A & B & 0 \\ \cline{2-10}  & A & 10\% & 7\% & 6\% & & A & 6\% & 11\% & 7\% \\ \cline{2-10}  & B & 10\% & 30\% & 3\% & & B & 11\% & 23\% & 13\% \\ \cline{2-10}  & 0 & 16\% & 11\% & 7\% & & 0 & 7\% & 13\% & 8\% \\ \hline  & & & T+ & & T- & & F+ & F- \\ \hline  & A-type success rate & \(\downarrow\) 9.8\% & \(\uparrow\) 50.6\% & \(\downarrow\) 25.9\% & \(\
earrow\) 13.8\% \\ \hline  & B-type success rate & \(\searrow\) 29.9\% & \(\
earrow\) 39.1\% & \(\searrow\) 18.4\% & \(\uparrow\) 12.6\% \\ \hline  & 0-type success rate & \(\downarrow\) 6.9\% & \(\uparrow\) 56.9\% & \(\uparrow\) 9.2\% & \(\downarrow\) 27.0\% \\ \hline  & Average Success rate & \(\downarrow\) 15.5\% & \(\uparrow\) 48.9\% & \(\
earrow\) 17.8\% & \(\
earrow\) 17.8\% \\ \hline \hline \end{tabular}
\end{table}
Table 5: NBC results for A, B, AB, and 0 (up) and A, B, and 0 (down).  
dimensionality from the original (18 \(\times\) 95) (peaks \(\times\) samples) to a (2 \(\times\) 95) (PCs \(\times\) samples). The differences between the PC-NBC algorithm and the random classification is statistically significant with \(p\) < 0.01 in every case but the misclassification of 0 samples as B (italics in the table). However, as shown in Table 6, the improvement is negligible, with a scarce enhancement in B and 0 correct type identification and a slight reduction in the false identification of A and 0 samples as B. This phenomenon aligns with the notion that the spectroscopic identification of the B antigen is easier than the identification of the A or of a lack of them.