Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other ajpect of this collection of information, including suggestions for reducing this burden, anxiety assessment instrument for widespread use, due in part to the unavailability of an easy-toadminister anxiety instrument that is not burdensome to either clinicians or critically ill patients.Objectives: To determine whether a single-item anxiety assessment instrument, the Anxiety Level Index (ALI), is a valid alternative to the State Anxiety Inventory (SAI) or the anxiety subscale of the Brief Symptom Inventory (BSI) in assessing state anxiety for patients with AMI.Methods: In this prospective multi-center study, 243 inpatients with AMI rated their anxiety using the SAI, the anxiety subscale of the BSI, and the ALI. Anxiety Level Index scores were compared to SAI and BSI anxiety subscale scores using Spearman's rho test and the BlandAltman method.Results: There were moderate, positive correlations between the SAI and the ALI (r = .52, P < .001) and between the ALI and the anxiety subscale of the BSI (r = .45, P < .001). However, the Bland-Altman method revealed a moderate bias between the ALI and the SAI and between the ALI and the anxiety subscale of the BSI. As anxiety scores increased, the level of disagreement became more pronounced in both comparisons.Conclusions: Although ALI scores were moderately and significantly correlated with scores on the SAI and the BSI anxiety subscale, the results of the Bland-Altman method indicate a lack of construct validity of the single-item measure. The quest continues to construct a simple selfreport measure of anxiety that is appropriate for critically ill patients with AMI.