I – Histopathology (positive for at least one of the following)

Focus score ≥ 1 (periductal lymphoid cell infiltration ≥ 50) in a 4 mm2 minor salivary gland biopsy

Focus score ≥ 1 (periductal lymphoid cell infiltration ≥ 50) in a 4 mm2 lacrimal gland biopsy
II – Oral Examination (positive for at least one of the following)

Abnormal findings in sialography ≥ Stage I (diffuse punctate shadows of less than 1mm)

Decreased salivary secretion (flow rate ≤ 10 ml/10 min according to the chewing gum test or ≤ 2 g/2 min according to the Saxon test) and decreased salivary function according to salivary gland scintigraphy
III – Ocular Examination (positive for at least one of the following)

Schirmer's test ≤ 5 mm/5 min and Rose Bengal test ≥ 3 according to the van Bijsterveld score

Schirmer's test ≤ 5 mm/5 min and positive fluorescein staining test
IV – Serological Examination (positive for at least one of the following)

Anti-Ro/SS-A antibody

Anti-La/SS-B antibody