MARC Coding

• MeSH topical descriptors are recorded in MARC 650 $a; qualifiers are recorded in MARC 650 $x (Cf. Module 5—Qualifiers)


• All MARC 650 fields have a second indicator “2” to show that they come from the MeSH thesaurus


• Primary subject headings are coded with a MARC 650 first indicator of “1”, secondary subjects are assigned the first indicator of “2.”

MARC Coding – Example 1

• A work on fire prevention in hospitals is coded as follows (both headings are primary)
  
  • 650 12 $a Fires $x prevention & control
    
  • 650 12 $a Hospitals

MARC Coding – Example 2

• A work on acupuncture for chronic low back pain (first heading is primary)
  
  • 650 12 $a Low Back Pain $x therapy
    
  • 650 22 $a Acupuncture Therapy
    
  • 650 22 $a Chronic Disease $x therapy