Development of saliva-based cardiac troponin I point-of-care test using alpha-amylase depletion: a feasibility study

• Published in: Coronary artery disease Vol. 34; no. 5; p. 351
• Main Authors: Westreich, Roi, Tsaban, Gal, Neumann, Yoav, Abu Salman, Amjad, Braver, Omri, Braiman, Dana, Zamed, Tali, Neuhaus, Zipora Feiga, Deutsch, Omer, Palmon, Aaron, Maimon, Nimrod, Zahger, Doron, Abramowitz, Yigal
• Format: Journal Article
• Language: English
• Published: England 01.08.2023
• Subjects: Biomarkers; Feasibility Studies; Humans; Point-of-Care Testing; Saliva; Salivary alpha-Amylases; Troponin I; Troponin T
• ISSN: 1473-5830
• DOI: 10.1097/MCA.0000000000001257

Cardiac troponin (cTn) is the biomarker of choice for detection of myocardial injury. There is a great need for simple point-of-care (POC) troponin testing among patients with chest pain, mainly in the prehospital setting. The purpose of this study was to evaluate the presence of cardiac troponin I (cTnI) in saliva of patients with myocardial injury using alpha-amylase depletion technique. Saliva samples were collected from 40 patients with myocardial injury who were tested positive for conventional high-sensitivity cardiac troponin T (cTnT) blood tests, and from 66 healthy volunteers. Saliva samples were treated for the removal of salivary alpha-amylase. Treated and untreated samples were tested with blood cTnI Rapid Diagnostic Test. Salivary cTnI levels were compared to blood cTnT levels. Thirty-six of 40 patients with positive blood cTnT had positive salivary samples for cTnI following alpha-amylase depletion treatment (90.00% sensitivity). Moreover, three of the four negative saliva samples were obtained from patients with relatively low blood cTnT levels of 100 ng/L or less (96.88% sensitivity for 100 ng/L and above). The negative predictive value was 93.65% and rose up to 98.33% considering the 100 ng/L cutoff. Positive predictive values were 83.72% and 81.58%, respectively. Among 66 healthy volunteers and 7 samples yielded positive results (89.39% specificity). In this preliminary work, the presence of cTnI in saliva was demonstrated for the first time to be feasibly identified by a POC oriented assay. The specific salivary alpha-amylase depletion technique was shown to be crucial for the suggested assay.