Carbamazepine (CBZ) has been reported as the most common culprit drug for 
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in several 
Asian countries including Thailand. A strong association between HLA-B*1502 and 
CBZ-induced SJS/TEN has been reported in Han Chinese but not in Caucasian and 
Japanese populations. A case-control study was conducted to determine whether 
HLA-B*1502 is a valid pharmacogenetic test for SJS/TEN caused by CBZ in a Thai 
population. Among 42 CBZ-induced patients with SJS/TEN, 37 (88.10%) patients 
carried the HLA-B*1502 while only 5 (11.90%) of the CBZ-tolerant controls had 
this allele. The risk of CBZ-induced SJS/TEN was significantly higher in the 
patients with HLA-B*1502, with an odds ratio (OR) of 54.76 [95% confidence 
interval (CI) 14.62-205.13, p = 2.89 x 10(-12)]. The sensitivity and specificity 
of HLA-B*1502 for prediction of CBZ-induced SJS/TEN were 88.10%. By assuming a 
0.27% as a prevalence rate of CBZ-induced SJS/TEN in a Thai population, the 
positive predictive value (PPV) and negative predictive value (NPV) of the 
HLA-B*1502 were 1.92% and 99.96%. Results from this study suggest that 
HLA-B*1502 may be a useful pharmacogenetic test for screening Thai individuals 
who may be at risk for CBZ-induced SJS and TEN.