The serum Raman spectra of patients with cholangiocarcinoma and cholangitis differ from that of healthy people in terms of Raman peak intensities and peak wavelength, representing a different metabolic component, according to a new study published in the journal Photodiagnosis and Photodynamic Therapy

For cholangiocarcinoma, the diagnostic sensitivity of serum Raman spectroscopy is better than traditional methods when combined with a support vector machine algorithm. Raman spectroscopy also has the advantage of being rapid and noninvasive compared to traditional clinical diagnostic methods.

“This study demonstrates that label-free serum Raman spectroscopy analysis technique combined with [support vector machine] diagnostic algorithm has great potential for noninvasive cholangitis and [cholangiocarcinoma] screening,” the researchers wrote. 

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To assess the feasibility of the approach to screen cholangiocarcinoma and cholangitis, a team led by Hui Zhao from the Department of Clinical Laboratory, The First Affiliated Hospital of Xinjiang Medical University, in Urumqi, China, collected Raman spectra from 38 patients with CCA, 49 patients with cholangitis, and 55 healthy controls.

“Normalized mean Raman spectra and spectral attributions reveal disease-specific biomolecular differences,” the researchers wrote. They also reported that serum Raman spectroscopy could identify cholangiocarcinoma and cholangitis when combined with a support vector machine algorithm. 

The diagnostic sensitivity of the approach was 89.5% for cholangiocarcinoma and 89.8% for cholangitis, and its specificity was 98.2% for cholangiocarcinoma and 94.6% for cholangitis. 

The authors concluded that their findings lay the ground for the potential use of Raman spectroscopy as a new and better method to clinically detect cholangiocarcinoma and cholangitis.

Cholangiocarcinoma is the name given to a group of rare malignant tumors that originate from cells of the biliary tree. It is the second most common primary malignancy of the liver after hepatocellular carcinoma. Cholangitis is the inflammation of the bile duct system, often due to a bacterial infection. 


Su N, Dawuti W, Hu Y, Zhao H. Noninvasive cholangitis and cholangiocarcinoma screening based on serum Raman spectroscopy and support vector machine. Photodiagnosis Photodyn Ther. Published online October 14, 2022. doi:10.1016/j.pdpdt.2022.103156