Validity of the saliva ferning test for the diagnosis of dry mouth in Sjögren's syndrome.

To study the validity of saliva ferning patterns as a diagnostic test for dry mouth in primary or secondary Sjogren's Syndrome (SS).Salivary smears were collected from 25 patients with Sjögren's syndrome in the fasting and nonfasting state. All 25 patients had symptomatic xerostomia and xerophthalmia and a positive Shirmer's test. Smears were taken from four sites, the cheek, lower lip, tongue, and saliva. Tests were done for rheumatoid factor, antinuclear antibodies, and anti-Ro(SS-A) antibodies. The salivary smears were air-dried and examined under a light and a polarizing microscope. Smears from 25 healthy subjects were also examined as controls.Three patterns of salivary secretion were identified, namely normal geometric ferning, reindeer antler ferning, and thick branching ferning. All Sjögren's syndrome patients had abnormal salivary smears, usually with a combination of reindeer antler ferning, thick branching ferning, and mucosal squames. This combination was seen in six of the 25 fasting specimens (24%); most of the remaining fasting samples showed the reindeer antler ferning. Reindeer antler ferning alone was found in five fasting and four nonfasting samples: this pattern was absent from five fasting and five nonfasting samples in which mucosal squames were the only abnormal finding. All nonfasting control samples exhibited normal geometric ferning. Smears from the cheek and saliva provided the most illustrative findings.The saliva ferning test is a simple, reproducible, and useful diagnostic aid in autoimmune xerostomia, approximately equivalent to Shirmer's test in xerophthalmia.