Background and purpose: Large B-cell lymphoma (LBCL) is the most common lymphoma subtype, with diffuse LBCL (DLBCL) accounting for 30%-40% of new lymphoma cases. The International Prognostic Index (IPI) is widely used for prognostic assessment in DLBCL. Clinical features associated with a poorer prognosis, such as advanced disease stage, could be a consequence of delayed diagnosis, which in turn may be influenced by a patient's socioeconomic status. While healthcare in Finland aims to ensure equal access to timely and high-quality treatment for all, disparities still exist. In this study we evaluated the impact of patients' socioeconomic status on their access to diagnostic procedures.

Patient/material and methods: Patient data was prospectively collected from seven hospitals between October 2014 and March 2020 in Finland. A total of 160 patients provided information regarding their diagnostic pathway and socioeconomic status via questionnaire. The data was combined with clinical data from patient records.

Results: The symptoms to treatment interval (STI) varied between age groups (p = 0.019), marital status groups (p = 0.023), and healthcare providers. In addition, age, income level, and occupational status (all p < 0.001) influenced which healthcare provider patients used as their first place of contact.

Interpretation: In this prospective study, we analyzed the impact of patients' socioeconomic status on treatment delays within the treatment pathway. Socioeconomic status was found to have a significant effect on these delays. The delays varied not only between different socioeconomic groups but also across different healthcare providers.

Keywords: delayed diagnosis; diffuse; health care disparities; health services accessibility; large B‐cell; lymphoma; socioeconomic factors.