Translation and Validation of the Modified A-DIVA Scale to European Portuguese: Difficult Intravenous Access Scale for Adult Patients

(1) Background: In Portugal, no accurate and reliable predictive instruments are known that could assist healthcare professionals in recognizing patients with difficult venous access. Thus, this study aimed to translate and validate the Modified A-DIVA scale to European Portuguese. (2) Methods: A methodological and cross-sectional study was conducted in two phases: translation of the Modified A-DIVA scale to European Portuguese following six stages proposed by Beaton and collaborators, and assessment of its psychometric properties in a non-probability sample of 100 patients who required peripheral intravenous catheterization in a Portuguese hospital. (3) Results: The European version of the Modified A-DIVA scale (A-DM scale) showed excellent inter-rater accordance scores, k = 0.593 (95% CI, 0.847 to 0.970), p < 0.0005. The A-DM scale’s criterion and construct validity was assessed through predictive, convergent, and correlational analysis with variables identified in the literature as associated with difficult peripheral intravenous access, with moderate to large magnitudes and statistical significance. (4) Conclusions: The A-DM scale is a reliable and valid instrument that can support healthcare professionals and researchers in the early identification of patients at risk of difficult peripheral intravenous access. Future validation studies are needed to test the A-DM scale’s applicability across clinical settings and in different patient cohorts.