Salivary and blood measurement of hs-cTnI and an adipokine panel in acute myocardial infarction: an exploratory paired-matrix study

Abstract Acute myocardial infarction (AMI) requires rapid biochemical confirmation, and saliva offers a non-invasive alternative to venous sampling. We measured high-sensitivity cardiac troponin I (hs-cTnI), Apelin, Elabela, Endoglin, Irisin and ischaemia-modified albumin (IMA) in paired blood and saliva from 60 selected AMI patients presenting within six hours of symptom onset and 30 healthy controls. In blood, Irisin, Elabela and Apelin were lower in patients and Endoglin higher (all p ≤ 0.020). In saliva, Endoglin was higher and Irisin lower (both p < 0.001), and only these differences survived Bonferroni correction and age restriction ( p ≤ 0.030); IMA differed in neither matrix. Blood and salivary values correlated strongly (Spearman rs 0.773–0.979, all p < 0.001), but Bland–Altman analysis showed proportional differences and wide limits of agreement. Salivary hs-cTnI assay signals completely separated the two groups; because elevated serum hs-cTnI was an inclusion criterion and no salivary assay was matrix-validated, this reflects case selection rather than diagnostic accuracy. The adipokine panel did not demonstrate an improvement over hs-cTnI in an exploratory cross-validation analysis. These findings provide preliminary evidence that the six analytes generate measurable assay signals in saliva and support further investigation, including matrix-specific validation and prospective evaluation in undifferentiated chest pain.