Objectives: We sought to reduce the 90% rate of missed diagnoses of panic-like anxiety (panic attacks with or without panic disorder) among emergency department patients with low risk noncardiac chest pain by validating and improving the Panic Screening Score (PSS). Method: A total of 1,102 patients with low risk noncardiac chest pain were prospectively and consecutively recruited in two emergency departments. Each patient completed a telephone interview that included the PSS, a brief 4-item screening instrument, new candidate predictors of panic-like anxiety, and the Anxiety Disorder Interview for the Diagnostic and Statistical Manual of Mental Disorders. Fourth Edition to identify panic-like anxiety. Results: The original 4-item PSS demonstrated a sensitivity of 51.8% (95% CI [48.4, 57.0]) and a specificity of 74.8% (95% CI [71.3, 78.1]) for panic-like anxiety. Analyses prompted the development of the Revised-PSS; this 6-item instrument was 19.1% (95% CI [12.7, 25.5]) more sensitive than the original PSS in identifying panic-like anxiety in this sample (χ2(1, N = 351) = 23.89 p < .001) while maintaining a similar specificity (χ2(1, N = 659) = 0.754, p = .385; 0.4%, 95% CI [−3.6, 4.5]). The discriminant validity of the Revised-PSS proved stable over the course of a 10-fold cross-validation. Conclusions: The Revised-PSS has significant potential for improving identification of panic-like anxiety in emergency department patients with low risk noncardiac chest pain and promoting early access to treatment. External validation and impact analysis of the Revised-PSS are warranted prior to clinical implementation.