IM Terms
IM terms are the main points of the article. Some common concepts that are frequently IM are:

• Organs (LIVER)
• Diseases (HEPATITIS)
• Organisms (HIV-1)
• Chemicals (ASPIRIN)
• Therapies (GENE THERAPY)
• Functions (DIGESTION)

However, if any of the above are not the focus of the article, they would be indexed as an NIM concept. The determination of whether a term is IM or NIM depends on the importance of the concept in the article at hand. Some terms can never be made IM. For example geographic terms, such as “NEW YORK CITY” or “AFRICA”, can not be made IM. In general, most articles require no more than 5 IM terms. The indexer can use more than 5 IM terms if the article demands it.