Development of Saliva-Based cTnI point-of-care Test: A Feasibility Study

Introduction

Cardiac troponin is the biomarker of choice for detection of myocardial injury . There is a great need for simple point of care troponin testing among patients with chest pain, mainly in the pre hospital setting. In this preliminary study we evaluate the feasibility of a novel, saliva-based cTn test.

Aim

1) To evaluate the presence of cTnI in saliva of patients with myocardial injury

2) to explore the feasibility a saliva-based point-of-care cTn assay

Methods: Saliva samples were collected from 32 patients with myocardial injury who tested positive for conventional cTnT blood tests, and from 13 healthy volunteers. 25 and 9 of these samples, respectively, were subjected to a series of advanced saliva processing procedures

Processed and unprocessed samples were tested with blood cTnI-RDT. Results were interpreted independently by two investigators and only concordant readouts were included in the analyses. Results were compared to blood cTnT levels

Results: Among the 25 positive samples subjected to advanced saliva processing procedures, 21 were confirmed positive by both investigators (sensitivities 84%). All 4 negative saliva samples were obtained from patients with relatively low blood cTnT levels of 155ng/L or less. Testing untreated samples, only 2 out of 32 were positive (sensitivities 6.25%). In both processed and unprocessed samples no false positive results were seen among healthy individuals (0 out of 9 and 0 out of 13, respectively), corresponding to a specificity of 100% for both processed and unprocessed groups. The negative predictive values for processed and unprocessed groups were 69.23% and 30.23 respectively. Statistical accuracies were 88.24% for the processed group and 33.33% for the unprocessed group.

Conclusion: This preliminary work demonstrates for the first time the presence of cTnI in saliva of patients with myocardial injury and possible detection of cTnI in clinical saliva samples utilizing a commercial blood-RDT platform.