15420
The lack of availability of a rapid and inexpensive screening test for the HLA - B * 58 : 01 allele is one of the obstacles to such screening .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None