How long can a tick be stored before sending it to a laboratory? - briefly
Ticks remain viable for diagnostic testing when kept refrigerated (≈4 °C) for up to 14 days, or frozen (−20 °C or colder) for several months without loss of pathogen DNA. Prompt shipment is recommended, but short‑term cold storage within these limits preserves sample integrity.
How long can a tick be stored before sending it to a laboratory? - in detail
Ticks may remain viable for diagnostic testing for varying periods depending on the preservation method and the intended analysis.
Refrigeration (4 °C) is suitable for short‑term holding. Most laboratories accept specimens kept at this temperature for up to 14 days without loss of DNA quality; some may extend to 21 days if the tick is placed in a moist container to prevent desiccation.
Freezing at –20 °C or colder preserves nucleic acids for extended intervals. Ticks stored frozen retain detectable DNA for at least six months, and RNA remains suitable for reverse‑transcription PCR if the sample is kept at –80 °C, with recommended processing within 2–3 months.
Ethanol fixation (70 %–95 %) provides long‑term morphological preservation and adequate DNA integrity for molecular assays. Specimens immersed in ethanol can be archived for years, although ethanol should be refreshed annually to avoid dilution by water absorption.
Key considerations for maintaining sample quality:
- Use a sterile, airtight tube or vial to prevent contamination.
- Label each container with collection date, location, and host species.
- Avoid repeated freeze‑thaw cycles; aliquot if multiple tests are anticipated.
- For pathogen detection that relies on RNA, minimize storage time and keep the sample cold (on ice) during transport, aiming for delivery within 48 hours.
In practice, the safest window for sending a tick to a diagnostic facility is within two weeks if kept refrigerated, or within several months if frozen or ethanol‑preserved. Exceeding these intervals may compromise detection of certain agents, especially those with labile RNA genomes.