TABLE 2.

Format of LIPID MAPS identifier (LM_ID) in the comprehensive classification system

Characters	Description	Example	Comments
1–2	Fixed “LM” designation	LM	Always LM
3–4	Two-letter category code	PR	One of eight categories
5–6	Two-digit class code	01	—
7–8	Two-digit subclass code	03	“00” when no subclass
9–10	Two-digit fourth level code	06	Only used for lipids with four levels
Last four digits	Unique four-character identifier within subclass or within fourth level	0002	First two of the last four digits are letters in the case of the Glycosphingolipid subclasses