To evaluate saliva ferning test in (SFT) diagnosis of xerostomia in patients with Sjögren's syndrome (SS).
Dried samples of freshly produced saliva from 78 patients diagnosed as SS according to european community criteria and 80 healthy controls were examined by light microscopy. The crystallization was classified into 4 types according to the ferning phenomenon: uniformity, branching, spreading and integrity (type I normal and type II, III, IV abnormal). Then, the 78 patients underwent labial salivary gland biopsy. According to Tarpley's classification of labial gland biopsy, > or = 2+ was considered positive.
(a) The sensitivity and specificity of SFT were 89.74% (70/78) and 83.75% (67/80) respectively. (b) Abnormal SFT was observed in 70/78 (89.74%) of SS and in 13/80 (16.25%) of normal controls. The differences of SFT in SS patients versus normal controls were significant (P < 0.01). (c) The sensitivity of SFT and labial gland biopsy had no significant differences (P > 0.05) as diagnostic tests in SS.
SFT was valuable as a diagnostic test in patients suspective of SS.