HLA-B and toxic epidermal necrolysis: This paper presents the results of that follow-up, namely (1) there has been a >90% decrease in the number of SJS/TEN cases associated with CBZ, (2) HLA-B*15:02 genotyping test orders steadily increased for the first three years and now appears to have reached a steady-state, (3) CBZ continues to be used in clinical practice, albeit at a slightly lower rate, (4) first-time use of CBZ has declined by less than half, and (5) LEV, another AED, has gained in popularity, especially among new users.