A COMPARISON OF 4 METHODS OF DATA PRESENTATION FOR LYSOSOMAL-ENZYME ACTIVITY IN GINGIVAL CREVICULAR FLUID

In previous studies, we have emphasized the importance of considering the methods used for analysis of gingival crevicular fluid (GCF). This study evaluated 4 different approaches for data presentation of lysosomal enzyme activity in GCF. GCF was collected from patients displaying at least 2 mm of clinical attachment loss at a minimum of 3 sites in the mouth (DA), and patients who did not display clinical attachment loss of 2 mm or more at any site in the mouth (DI), during a 3-month interval following entry into a longitudinal trial. GCF was collected by the timed intrasulcular placement of precut filter paper strips. 16 to 28 individual GCF samples were collected from each patient. The lysosomal enzymes studied were B-glucuronidase (BG) and arylsulfatase. The mean values for the DA and DI groups at baseline and 3 months are reported. The results indicate that when the data is expressed as total enzyme activity (unit activity) per 30-s collection (UA) or UA .times. GCF volume (.mu.l) per mm of probing depth, the DA group demonstrated significantly greater mean values than the DI group at baseline and 3 months. In contrast, when the data was expressed as concentration (UA/.mu.l), or UA per mm of probing depth, differences between the DA and DI groups were observed only at the 3-month evaluation. The difficulty in using concentration when reporting GCF lysosomal enzyme activity is emphasized by comparison of the data from the DA group and the high and low enzyme activity subsets of the DI group. At baseline, the DA group had a significantly lower BG concentration than the DI high enzyme subset, but a significantly higher BG concentration compared to the DI low enzyme subset. In addition, determination of true volume presents a potential source of error in the calculation of concentration of any factor in GCF. When GCF is collected for diagnostic purposes with a timed insertion of a precut filter strip, our data indicates that the preferred method of presentation for lysosomal enzyme activity is UA.