BACKGROUND: Alpha-amylase levels can be used to quantify the psychological stress. A hand-held salivary alpha-amylase (sAA) monitor was recently developed for measuring sAA levels. This study investigated the inter- and intraobserver reliability of this novel instrument. METHODS: Saliva was collected from 32 healthy volunteers. To determine the interobserver reliability, three observers measured the sAA levels in 10 samples. To determine the intraobserver reliability, one observer performed consecutive sAA measurements in 32 samples. The sAA levels in these 32 samples were also measured by a conventional laboratory enzymatic analysis, and these measurements were compared with those obtained using the hand-held monitor. RESULTS: Intraclass correlation coefficients indicated excellent inter- and intraobserver reliability (0.99 and 0.92, respectively). The results from the monitor and the lab assay showed a significant positive correlation (r = 0.96, p < 0.001). CONCLUSIONS: These results suggest that the hand-held monitor is highly reliable for measuring the sAA level.
BACKGROUND: Alpha-amylase levels can be used to quantify the psychological stress. A hand-held salivary alpha-amylase (sAA) monitor was recently developed for measuring sAA levels. This study investigated the inter- and intraobserver reliability of this novel instrument. METHODS: Saliva was collected from 32 healthy volunteers. To determine the interobserver reliability, three observers measured the sAA levels in 10 samples. To determine the intraobserver reliability, one observer performed consecutive sAA measurements in 32 samples. The sAA levels in these 32 samples were also measured by a conventional laboratory enzymatic analysis, and these measurements were compared with those obtained using the hand-held monitor. RESULTS: Intraclass correlation coefficients indicated excellent inter- and intraobserver reliability (0.99 and 0.92, respectively). The results from the monitor and the lab assay showed a significant positive correlation (r = 0.96, p < 0.001). CONCLUSIONS: These results suggest that the hand-held monitor is highly reliable for measuring the sAA level.