Lactate dehydrogenase activity in gingival crevicular fluid collected with filter paper strips: analysis in subjects with non‐inflamed and mildly inflamed gingiva

Abstract

A previous study of lactate dehydrogenase (LDH) in gingival crevicular fluid (GCF) suggested that the concentration is 10 to 25 times that of serum (means = 2300 international units/1 versus 100 IU/1 for serum). That study used capillary tubes to collect microliter amounts of GCF. Since invasive collection techniques can influence GCF flow, we evaluated LDH activity in GCF collected by filter strips. GCF was collected in a standardized fashion from 10 subjects with mild inflammation (GI = 0.5-1.0) and 10 subjects without evidence of gingival inflammation (GI = 0). Our results indicate that LDH volume activity was greater for subjects with GI = 0 (means = 105,529 IU/1) than for subjects with GI = 0.5-1.0 (means = 77,661 IU/1), but the difference was not significant. LDH total unit activity was significantly greater in subjects with GI = 0.5-1.0 versus GI = 0 (means = 0.048 IU versus means = 0.0242 IU, P less than 0.0001). The relationship of LDH volume activity to GCF volume, the regression lines fit to the data, and calculation of LDH total unit activity were important for analysis of enzyme activity in GCF.