Quick answer
A usable outbreak line list preserves the person, illness episode, onset information, location history and test events without counting every result as a new person. Agree the case definition and reporting scope with qualified infection-prevention staff and public health, then retain a dated snapshot for each submitted summary.
Define the observation unit
The CDC respiratory surveillance resource describes person-level collection for residents and staff, including location, signs and symptoms, diagnostic testing and outcomes. It is a March 2019 data-collection resource, not current pathogen-specific clinical guidance.
The CDC nursing-home respiratory toolkit updated September 24, 2026 calls for active surveillance and coordination with local or state public health when an outbreak is suspected or confirmed. Qualified professionals establish the actual case definition and clinical response. The administrative job is to preserve data that can support that work.
Reconcile five records into three people
A fictional source extract contains five rows:
| Source row | Person and event | Reconciliation |
|---|---|---|
| 1 | Resident A, first test | One test linked to A's reviewed episode |
| 2 | Resident A, repeat test | Additional test, not automatically another person or episode |
| 3 | Resident B, observation in Room 12 | B's episode begins in the recorded location history |
| 4 | Resident B, later observation in Room 20 | Same person after a move; preserve both locations and times |
| 5 | Employee C, illness report | Separate staff record under the applicable definition |
The extract represents three people, not five. Whether it represents three reportable cases depends on the agreed definition and professional review. The database must preserve that distinction rather than automatically turning every source row into a case.
For Resident B, assigning all exposure history to the current Room 20 would erase relevant earlier location information. For Employee C, a staffing assignment may involve more than one unit; record the relevant work-location history through the authorized process without broadly disclosing employee medical details.
Keep unknown dates unknown
Separate symptom onset, first observation, specimen collection, result and notification times. If onset is uncertain, retain that uncertainty and any later supported clarification. Do not substitute the laboratory result date merely because it is the only populated field.
A case definition can change as public health learns more. Version the definition and preserve the classification basis for each reporting snapshot. If a later correction changes the count, explain the change instead of overwriting the previously submitted summary with no history.
The line list should also distinguish pending results, invalid results and confirmed results as appropriate to the actual testing process. Administrative categories must not be treated as clinical diagnoses.
Produce a reconciled public-health snapshot
The person-level snapshot correctly shows two residents and one employee under the agreed reporting scope. A draft unit summary instead counts Resident A's repeated test as an additional resident and shows three residents. Reconciliation corrects that draft to two residents before submission. If an incorrect summary had already been sent, preserve the original submission, corrected version and reason for the change; keep the person-level evidence available to the authorized investigation team.
Before submission, reconcile the summary to the line-list snapshot and the actual jurisdictional definition. A weekly NHSN total may legitimately differ because of population, period or measure rules. Explain that difference rather than forcing every report to match one local number.
Use authorized secure channels and disclose only the information required for the actual recipient and purpose. A deidentified management chart and a public-health investigation file may need different detail.
The finished artifact is a dated, reproducible count with person/episode/test links and location history. For a platform buyer, the five-row example tests whether clinical, laboratory and workforce data can support investigation without inflating cases or losing the chronology.
Questions & answers
Is one positive test always one new case?
No. Multiple results can relate to the same person and episode. Apply the current case definition and preserve test events separately.
Can room number identify a case?
No. Residents can move and rooms can have different occupants. Use a stable internal identity with the relevant location history.
Does a line list replace required NHSN reporting?
No. It supports investigation and reconciliation. NHSN and jurisdictional reports have their own populations, definitions and submission rules.
Primary sources
- CDC LTC Respiratory Surveillance Line List and Outbreak Summary
- CDC Viral Respiratory Pathogens Toolkit for Nursing Homes
Use the cited source and its applicable version when making a facility-specific decision. These guides explain operational evaluation methods; they are not individualized clinical, coding, or legal advice.