OBJECTIVE Sjögren's syndrome is a chronic inflammatory disease. The detection of chronic inflammatory infiltrates containing >50 lymphocytes (lymphocytic focus) per 4 mm2 tissue in minor salivary gland biopsies is a diagnostic parameter of the disease. The aim of the study was to examine if an increase in the tissue area of a single minor labial salivary gland biopsy through serial histological sections in patients affected by primary Sjögren's syndrome could facilitate the detection of the diagnostic focus score (grades >1 or >2). METHODS We observed 24 labial salivary gland biopsies from patients affected by primary Sjögren's syndrome, diagnosed according to the clinical-laboratory criteria proposed by the American-European Consensus Group. The analysis was carried out on sections (n= 72) obtained at three different levels at 200 micrometers from one another. The serial sections regarding the 3 levels were reviewed by the same oral pathologist, who detected both the total number of foci, and their surface, calculating a cumulative focus score. RESULTS No significant correlation was found between the number of lobules per histological section and the focus score (Pearson correlation 0.363, p= 0.01). No significant variation in focus score distribution was identified in the three serial histological levels at 200 micrometers from one another. From the comparison between the number of lobules observed and the focus score grade, no direct proportionality between the amount of parenchyma analyzed and the focus score was found. CONCLUSIONS The focus score remained unchanged in the serial sections at different depths.