What to know
A false-positive investigation can be initiated by a laboratory, TB Program, healthcare provider, or submitter. Collaboration among the laboratory, TB Program, healthcare providers, and submitters in a potential false-positive investigation is essential.
Notifications
False-positives may be caused by a variety of reasons, including laboratory cross-contamination, contamination of a clinical device or container during specimen collection, and clerical error prior to specimen receipt in the laboratory.
If the laboratory determines that a false-positive result has potentially occurred, the laboratory should notify the TB Program and healthcare provider in a timely manner. When reviewing patient results and epidemiologic factors during routine surveillance activities, TB Programs may notice results that are not consistent with patient history. In this situation, the TB Program should notify the laboratory and healthcare provider immediately.
When test results are questioned as potential false-positives, justification should be provided when requesting or initiating an investigation. This justification should include:
- The reason for the investigation,
- Patient identifiers,
- Laboratory/specimen accession numbers including date of receipt in the laboratory,
- Patient clinical presentation and history, and
- Patient test results from all laboratories where testing was performed.
After communication is established with all essential persons, an investigation strategy should be developed for every false-positive inquiry. Consideration should be given to:
- Laboratory procedures and policies,
- Patient clinical presentation and history, and
- Specimen collection practices.
Collaboration among the laboratory, TB Program, healthcare providers, and submitters in a potential false-positive investigation is essential.