Influenza Sample Preparation and Shipping Guidelines
The accurate diagnosis and surveillance of influenza rely heavily on the quality of clinical specimens collected and the integrity of the samples during transport to the laboratory. Proper preparation and shipping are critical to ensure that viral pathogens remain viable for detection and characterization.
Specimen Collection and Preparation
For influenza, the preferred specimens are typically nasopharyngeal (NP) swabs, nasal swabs, or throat swabs. To ensure the highest quality results, follow these preparation steps:
- Collection Media: Always use sterile synthetic fiber swabs with plastic or wire shafts. Avoid calcium alginate swabs or swabs with wooden shafts, as they may contain substances that inactivate viruses or inhibit PCR testing.
- Transport Media: Place the swab immediately into a sterile vial containing 23 mL of viral transport medium (VTM) or universal transport medium (UTM).
- Labeling: Clearly label each specimen container with a unique patient identifier, date of collection, and specimen type using a permanent, waterproof marker.
- Storage Prior to Shipping: If the samples cannot be shipped immediately, store them at 28C (refrigerated). Do not freeze unless specifically instructed by the receiving laboratory, as repeated freeze-thaw cycles can degrade viral RNA.
Shipping Checklist
When preparing samples for transit, adhere to national and international regulations regarding the transport of biological substances. Use the following checklist to ensure compliance and sample integrity:
Shipping Preparation Checklist
- Primary Receptacle: Ensure the specimen vial is tightly sealed. Parafilm or tape can be used to further secure the cap to prevent leakage.
- Secondary Packaging: Place the labeled vials into a leak-proof secondary container (such as a sealable biohazard bag) containing sufficient absorbent material (e.g., paper towels or specialized pads) to soak up the entire volume of liquid if a spill occurs.
- Outer Packaging: Place the secondary container inside a rigid outer shipping box. Ensure the box is durable enough to withstand the rigors of transit.
- Temperature Control: Include enough cold packs (frozen gel packs) to maintain a temperature of 28C for the duration of the shipment. Avoid direct contact between the ice packs and the specimen vials to prevent freezing.
- Documentation: Place a copy of the completed laboratory requisition form in a separate waterproof bag. Ensure it includes patient history, clinical symptoms, and vaccination status.
- Hazard Labeling: Affix the appropriate "Biological Substance, Category B" label (UN 3373) to the outside of the package. Ensure the contact information for both the sender and the receiving laboratory is clearly visible.
Best Practices for Transit
To minimize the risk of sample degradation, coordinate shipping times carefully. Aim to ship specimens early in the week to avoid weekend delays at courier facilities or holding areas. Always notify the receiving laboratory in advance that a shipment is incoming, providing tracking information whenever possible.
By following these standardized procedures, healthcare providers can ensure that influenza specimens arrive in optimal condition, enabling timely and accurate diagnostic results that are essential for effective public health response and patient care.
