How should a tick be stored before analysis? - briefly
Store the specimen in 70 % ethanol and keep it frozen at –20 °C to preserve DNA and morphology. If live analysis is needed, maintain the tick in a humid chamber at 4 °C and process within 24 hours.
How should a tick be stored before analysis? - in detail
Proper preservation of ticks before laboratory examination is essential for accurate morphological identification, molecular testing, and pathogen detection. The following guidelines address each critical aspect of storage.
Ticks should be placed in a tightly sealed container that prevents desiccation and physical damage. Preferred vessels include 1.5‑ml microcentrifuge tubes, cryovials, or small vials with screw caps. Insert a sterile, dry cotton or paper pad to absorb excess moisture if specimens are wet, but avoid direct contact with liquid that could cause swelling or degradation.
Temperature control depends on the intended analysis:
- Morphological studies – store at 4 °C in a refrigerator. Maintain humidity at 70–80 % using a dampened cotton ball inside the container; this prevents shrinkage while avoiding mold growth. Examine specimens within 2–3 weeks; longer storage may alter cuticular features.
- Molecular assays (PCR, sequencing) – freeze at –20 °C or –80 °C. Prior to freezing, remove any residual blood or host tissue with a sterile brush. For long‑term preservation, submerge ticks in 70 % ethanol before freezing; ethanol penetrates tissues and stabilizes nucleic acids. Ensure the ethanol volume is at least ten times the tick volume.
- Pathogen culture – keep at 4 °C in sterile saline or phosphate‑buffered saline (PBS) supplemented with 1 % antibiotic–antimycotic solution. Use this method only when live organisms are required and process samples within 24 hours.
If ethanol is used, replace the fluid after 24 hours to remove dilution of the preservative and maintain concentration. For ticks destined for both morphological and molecular work, split the specimen: preserve one half in ethanol for DNA extraction and retain the other half dry at 4 °C for later microscope examination.
Label each container with collection date, location, host species, and unique identifier. Use waterproof, archival‑quality ink to prevent smearing. Attach a barcode or QR code when handling large numbers of specimens to reduce transcription errors.
When transporting samples, maintain the chosen temperature condition with insulated coolers, ice packs for refrigeration, or dry ice for frozen specimens. Avoid repeated freeze‑thaw cycles; if thawing is unavoidable, process the tick immediately and refreeze any remaining tissue.
Adhering to these protocols preserves structural integrity, prevents nucleic‑acid degradation, and maximizes the reliability of downstream diagnostic results.