Introduction: The gold standard method for diagnosing primary hyperhidrosis (PHH) is based on seven patient-reported criteria. By determining an individual criterion’s diagnostic accuracy, one can identify short-version classification models. Methods: In this cross-sectional study, data were collected from Danish blood donors in 2021. Cohen’s kappa and diagnostic accuracy were determined by comparing each criterion with the gold standard method. Results: The study included 1,039 participants. Of them, 59 (5.7%) had PHH and 980 (94.3%) were classified as control individuals. The PHH major criterion “focal visible excessive sweating for at least 6 months without an apparent cause” had the highest prevalence in the participants with PHH compared to the control individuals (100% vs. 0.6%; p < 0.0001). The agreement between this criterion and PHH was Cohen’s kappa = 0.95 (95% confidence interval [CI] 0.91–0.99), and its sensitivity was 1.00 (95% CI 0.94–1.00) and specificity 0.99 (95% CI 0.99–1.00). The other criteria showed lower agreement and diagnostic accuracy. Conclusions: The PHH major criterion showed near-perfect agreement and near-equal diagnostic accuracy compared with the gold standard method. This single criterion can be used as a short-form version to screen for PHH. Determination of reproducibility in independent populations is warranted.