Reliability of Toluidine Blue Vital Staining in Detection of Potentially Malignant Oral Lesions - Time to Reconsider

Being simple and inexpensive toluidine blue has been in use for more than two decades for the detectionof potentially malignant oral lesions (PMOL’s) and malignant lesions. Although there has been concensusthat staining often assists in the identification of these lesions, results have been diverse. In most studies falsenegative were not recorded as biopsies of lesions that did not retain toluidine blue were not performed. Thusthe present study attempted to evaluate the efficacy of toluidine blue vital dye for detection of PMOL’s. Thestudy included 47 biopsies(TBP:35 and TBN:12), of which 23 cases were confirmed as dysplastic(TBP=17 andTBN=6), 7 as hyperkeratosis (TBP=4 and TBN=3), 8 as epithelial hyperplasia(TBP=6 and TBN=3) and 5 as otherbenign lesions(TBP=4 and TBN=1). The validity test revealed a senstivity of 73.9% and specificity of 30%. Thepositive predictive value was 54.8% and negative predictive value of 50%. The study intends to highlight thefalse negative result (26.1%) which was mainly attributed to mild dysplasia and the false positive (32.6%) whichincluded hyperkeratosis, hyperplasia, lichen planus and traumatic ulcer. The study concludes that toludine bluestaining should not blindly direct the clinician’s opinion, and strongly discourages the use of toluidine blue as ascreening test and the results should be interpreted with caution.