BackgroundDexterous dysfunction is a bothersome patient‐reported symptom of Parkinson's disease (PD). Current clinical assessments do not directly evaluate goal‐directed hand function. This project sought to determine the capability of the electronic Manual Dexterity Test (MDT) to characterize dexterity across a range of PD patients.ObjectivesTo objectively quantify manual dexterity in individuals with PD using a self‐administered manual dexterity test.MethodsTwo hundred and forty‐nine PD patients completed trials of the MDT with each upper extremity (UE) both while ON and OFF antiparkinsonian medication. Differences in MDT by medication state, more vs less affected UE, and Hoehn and Yahr (H&Y) stage were evaluated using linear mixed models. The relationships of trial duration to MDS‐UPDRS II patient quality of life (QoL) questions for eating, dressing and hygiene were also evaluated.ResultsMDT duration was significantly shorter ON medication (26.3 seconds) compared to OFF medication (27.2 seconds) (P < 0.001). Similarly, MDT duration was significantly shorter for less (25.8 seconds) compared to more (27.6 seconds) affected limb (P < 0.001). Trial durations increased with H&Y stage (P < 0.001 for trend). MDT performance was related to MDS‐UPDRS II questions for eating, dressing, and hygiene performance (P < 0.001).ConclusionsThe MDT provides an objective and quantitative assessment of dexterity. The time to complete the MDT was sensitive to changes in medication state, more and less affected UE, disease severity, and important activities of daily living. The MDT has potential for utilization in precise tracking of manual dexterity over the course of PD.