[Evaluation of mental stress tests among medical students based on salivary sample collected just before the national license examination].

We investigated salivary amylase (sAMY) and chromogranin A (sCgA) in students before the national license examination in order to investigate the relationship between stress biomarkers and the Profile of Mood States (POMS) psychological test. Fifty-one medical students that provided informed consent were tested for sAMY activity and sCgA concentration by means of the amylase monitor method (NIPRO) and an ELISA kit (Yanaihara), respectively. The POMS psychology test (shortened form) was purchased from Chiba Test Center, and all students fully answered the lifestyle questionnaires. Based on answers to the questionnaires, students were divided by mental burden into three groups: I all"; II "large"; and III "very large". Scores for "T-A", "D" and "A-H" on the POMS test were significantly higher in groups II and III when compared with group I. Mean TMD scores calculated from the 6 items on the POMS test increased significantly with mental burden. The mean levels and 95% confidence interval (CI) of sAMY activity in the 3 groups were as follows: I, 27.7 (95% CI: 13.7-41.7) KIU/L; II, 29.1(95% CI: 22.4-35.7) KIU/L; and III, 26.9 (95% CI: 15.2-38.6) KIU/L. Mean sCgA concentrations were: I, 4.4(95% CI: 0-9.4) pmol/mg; II, 4.3(95% CI: 2.0-6.7) pmol/mg; and III, 10.9 (95% CI: 6.8-15.0) pmol/mg. There were no significant differences between these mean levels. However, Spearman's rank-correlation coefficient analysis for "T-A", sAMY and sCgA showed a stronger correlation between "T-A" and sCgA than between "T-A" and sAMY (p < 0.05). In conclusion, sCgA was more useful biomarker to evaluate the psychological stress before the national license examination than sAMY.