21982
Skin and serum samples were collected over 96h , IFN alpha levels were determined by an antiviral assay , and half - life ( t1 / 2 ) and elimination ( k ) rates were calculated .
 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