Loop Validation Index
A Temple Segment is a template that Loop Segments use. Loop Segments are the only segments added to the loop structure.
Sometime Template Segments are used as the first segment in a loop. Examples include, ST, NM1, ENT, etc. In order for EDIValidator component to decipher if the segment is actually the correct loop segment it usually looks at the value of the first element of the segment. Usually the element will have one or more accepted values. If the first element contains this value then the loop is valid. Most of the HIPAA specifications uses the first element.
In some cases however the value of the first element of the segment is not used. You can modify the loop validation index from the default of 0 (the first element), to any desired element.
An example of where the loop validation index must be changed is in the 820 (Payroll Deducted and Other Group Premium Payment for Insurance Products) HIPAA implementation guide. The loop validation index of the ENT segment must be changed from 0 to 1.