Quantification Of Triglyceride Levels In Human Blood With Coronary Heart Disease By Terahertz Time-domain Spectroscopy

In recent years,the incidence of coronary heart disease(CHD)has been increased.Coronary heart disease has a high mortality and disability rate,which seriously threatens the life safety of the patients and reduces their quality of life.In a clinical setting,fresh hemolysis-free serum is obtained mainly by routine venous blood collection and the triglyceride(TG)concentration is determined by an automatic biochemical analyzer.The instrument bases on an enzymatic chemical method.Recently,terahertz time domain spectroscopy(THz-TDS)has been suggested as a feasible and sensitive tool to estimate the collective bending vibrations of the hydrogen bonds of water molecules in aqueous solutions.Blood has approximately 80% water and contains various types of the polarized solutes.In the aqueous solution composed of water,THz wave has been shown to be a sensitive tool for investigation of the bending vibrations of the hydrogen bond groups of the water molecules.THz absorption of an aqueous solution is highly sensitive to the concentrations of various solutes because the polarized solutes can change the collective bending vibration of hydrogen bonds;the strong absorption of THz wave by the water molecules is compatible with the non-destructive detection of the water content and distribution.Moreover,the photon energy of the THz wave is only a few parts per million of the X-ray photon energy,which is lower than the bond energy of various chemical bonds.Therefore,THz radiation will not lead to photoionization and will not harm the human body,which is suitable for blood detection in the human body.This paper focuses on using THz-TDS to study the concentrations of TGs in human blood.The work mainly includes the following aspects:(1)103 human blood samples(including 10 normal people and 93 patients with coronary heart disease)was measured by THz-TDS.The study found that the THz absorption coefficients with the different TG levels in human blood had great differences,and the results indicate that THz-TDS can be used to quantify the TG levels in human blood.(2)Based on the TG concentrations and the corresponding THz absorption coefficients,the Pearson correlation analysis demonstrated that the THz absorption coefficients have a significant negative linear correlation with the TG concentrations.The correlation between THz absorption coefficient and the TG concentrations was the highest at 0.2 THz.(3)Comparisons between the THz measurements at 0.2 THz and an automatic biochemical analyzer were performed using an additional 20 blood samples,and the results confirmed that the relative error was less than 15%.Our ex vivo human blood study indicates that the THz technique can be used to assess blood TG levels in clinical diagnostic practice.