How to Interpret the "Index Date" Field

An index date of “0” may refer to various time points in a patient’s journey (e.g., date of diagnosis, date of molecular testing, etc.) based on an algorithm developed by our molecular testing vendor. An illustration of the rule set utilized to generate index date is provided below.
The blanks in the “effective_time_from_index” column can be blank for up to 3 reasons

1. The year is known, but the day and month are unknown
2. If all date elements for a given event are unknown
3. The patient has any clinical history >89 years in their record