Possible reasons why the duplicate adverse reaction report number indicated in the Duplicate or Linked Adverse Report Report (AER) Number
field did not appear in the list of retrieved reports:
- Time period searched does not cover the Initial Received Date for the duplicate reports. For example, a search was performed for the period January 1, 2008 to December 31, 2008. A duplicate report for report X (report Y) was received in February 2009. The report X will indicate the duplicate report Y in the Duplicate or Linked AER Number field but report Y will not appear in the list of retrieved reports.
- Report X has been determined to be a duplicate of report Y due to the patient identifiers, suspect product, dose, therapy dates and date of onset, however, the description of the AR within report X is not identical to the adverse reaction described in its duplicate report Y. Adverse reaction term selection is based on the reporter's description of the adverse reaction; therefore the same adverse reaction described differently by 2 individual reporters would result in different adverse reaction terms selected. The duplicate might not appear in the list of retrieved reports depending of the adverse reaction term searched. For example, report X reports Anaphylactic shock as the adverse reaction and report Y reports only the symptoms and no diagnosis (i.e. Hypotension, Hyperventilation, Dyspnea, Bronchospasm, etc.) therefore, if a search is performed with the adverse reaction term Anaphylactic shock only, it will not retrieve the report Y.
- When adverse reaction reports for a single patient are based on literature articles reported by market authorization holder, as per their regulatory reporting requirements, the suspect product may be dependent on the particular market authorization holder that is reporting it. This means that a product that is suspect in one report may been a concomitant in the duplicate report.