Prediction and diagnosis of attachment loss by enhanced chemiluminescent assay of crevicular fluid alkaline phosphatase levels

The current study aimed to apply a novel enhanced chemiluminescence assay i n the analysis of gingival crevicular fluid (GCF) alkaline phosphatase (ALP ) levels from patients with untreated adult periodontitis. 3666 sites in 25 patients were monitored prior to and after attachment loss was detected wi th a Florida disc probe. Parameters assessed were, relative attachment leve l, probing pocket depth, occurrence of bleeding on probing (single episode) , GCF volume (mu l), total ALP levels (mu IU/30 s sample time) and ALP conc entration (IU/l). After recruiting patients to the study, all measures were taken at baseline and 3 months later, prior to the institution of non-surg ical periodontal therapy at active sites. Thresholds for determining attach ment loss were calculated using a modification of the tolerance method. The mesio-buccal sites of all teeth had GCF samples collected. The size of ind ividual patient thresholds used to define whether attachment loss had occur red, was dependent upon the discomfort felt by that patient during electron ic probing, with a positive correlation existing between discomfort on prob ing(10 cm visual analogue scale) and threshold size (R=0.52,p<0.049). A tot al of 274 sites (7.5%) experienced attachment loss of which 39 sites had GC F samples available for analysis. Total ALP levels were significantly highe r at baseline for sites that progressed to attachment loss than paired cont rols (p<0.003), but all other parameters showed no differences (p>0.1). The re were significant increases in total ALP levels and GCF volumes for activ e sites between baseline and 3 month measures (p<0.01), but not for control sites or lest site ALP concentration (p>0.8). The diagnostic accuracy for GCF ALP as a predictor of future attachment loss (threshold 900 mu IU/30 s) was 64%, with + ve and -ve predictive values of 62% and 68%. When a thresh old of 1300 mu IU/30 s was selected for ALP as a marker of recent or curren tly active disease, diagnostic accuracy and +ve/-ve predictive values were 77% and 77%/76%, respectively. These results indicate that total GCF ALP le vels may serve as a predictor of future or current disease activity.