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Timing Relative to a Fixed Reference Time Point

--STRTPT, --STTPT, --ENRTPT, and --ENTPT

• Variable --STRTPT represents the start of an observation relative to a reference time point.
• Variable --ENRTPT represents the end of an observation relative to a reference time point.
• The variables --STRTPT and --ENRTPT represent the start 

The description or date and/or 
time of a time point that acts as 
a fixed reference for 
characterizing the start of an 
observation

• contain values similar to --STRF and --ENRF, but may be anchored with any timing description or date/time value expressed in the respective --STTPT and --ENTPT variables, and are not limited to the study reference period. Unlike the variables --STRF and --ENRF, which for all domains are defined relative to one study reference period, the timing variables --STRTPT, --STTPT, --ENRTPT, and --ENTPT are defined by each sponsor for each study. Allowable values for --STRTPT and --ENRTPT are as follows.

If the reference time point corresponds to the date of collection or assessment:

• Start values: An observation can start BEFORE that time point, can start COINCIDENT with that time point, or it can be UNKNOWN when it started.
• End values: An observation can end BEFORE that time point, can end COINCIDENT with that time point, can be known that it did not end but was ONGOING, or it can be UNKNOWN when it ended or if it was ongoing.
• AFTER is not a valid value in this case because it would represent an event after the date of collection.

If the reference time point is prior to the date of collection or assessment:

• Start values: An observation can start BEFORE the reference point, can start COINCIDENT with the reference point, can start AFTER the reference point, or it can be UNKNOWN when it started.
• End values: An observation can end BEFORE the reference point, can end COINCIDENT with the reference point, can end AFTER the reference point, can be known that it did not end but was ONGOING, or it can be UNKNOWN when it ended or if it was ongoing.

Although "DURING" and "DURING/AFTER" are in the STENRF codelist, they describe timing relative to an interval of time rather than a point in time, so are not allowable for use with --STRTPT and --ENRTPT variables.

f instances of an activity are scheduled at planned time intervals relative to a fixed reference point (e.g., administration of a dose), the following timing variables should be used:

• --TPTREF: the description of the fixed reference point event or "anchor" from which the planned observation will be made, usually the dose (e.g., "Day 1 Dose"; "Day 1, Dose 1").
• --ELTM: the planned elapsed time from the fixed reference point event (e.g., a dose) to the planned observation, in ISO 8601 format, which is usually also reflected in the --TPT label. For example, if an observation is planned for 30 minutes after the day 1 dose (e.g., --TPT = "30 minute postdose"), --TPTREF would be "Day 1 Dose" with an --ELTM of PT30M.
• --TPT: the label for the time point relative to –TPTREF planned observation, typically reflecting --ELTM. For example, if --TPT is "30 minute postdose," then --ELTM would be PT30M; a "1 hour" --TPT would have an --ELTM of PT1H .
• --TPTNUM: indicates the order of the time points (TPT) relative to the fixed reference point (TPTREF) for the category and/or subcategory (CAT/--SCAT) of data within a domain. The ordering/sequence number of the time point (e.g., 1, 2, 3) is sponsor-defined, but is usually at least unique within the given interval. For example, for a given day with 3 time points (pre-dose, 30 minutes post-dose, 1 hour post-dose), --TPTNUM could be 1 for pre-dose, 2 for 30 minutes post-dose, and 3 for 1 hour post-dose, to establish their relative order.

For each unique planned time point (--TPT), there must be a one-to-one relationship between the values of --TPT and --TPTNUM. Uniqueness for these time points is determined by a combination of the domain, fixed reference point (TPTREF), and (if present) category and/or subcategory (CAT/--SCAT).

Other variables (e.g., --TESTCD, --METHOD) may also be needed in some cases to define uniqueness. When this occurs, clarification should be provided as a comment to --TPTNUM in the define file.

--RFTDTC is used to represent the actual date/time of the fixed reference point (--TPTREF).