Exploring pre-analytical factors for the optimisation of serum diagnostics: Progressing the clinical utility of ATR-FTIR spectroscopy

Data quality and reproducibility are vital for robust, reliable and consistent diagnostic techniques within clinical environments. Most variance within clinical laboratories occur within the pre-analytical phase, prior to obtaining and analysing data. Herein, we investigate pre-analytical considerations for the spectroscopic analysis of blood serum for the purpose of clinical diagnostics. Variables within sample collection, storage and preparation are explored in order to evaluate their effects on the spectral outcome, including; differences between sample collection tubes, centrifugal speed and time, short and long-term storage conditions, individual analyst technique, sample volumes, environment of sample batches, as well as various drying techniques. Exploratory data analysis using principal component analysis was implemented to unearth spectral variance not immediately observable. Minor spectral variations were observed within each experiment; however, these were not considered significant differences as a result of these varying experimental factors. Variation between different operator techniques when preparing samples was observed, yet can be resolved with appropriate standard operating procedures, regardless of other factors such as sample volume and storage conditions. The findings within this report suggest that experimental variations within a laboratory, or between different laboratories, does not significantly affect the spectral outcome, and with good laboratory practice and careful sample handling results should be consistent and reliable.