The proper transportation of blood samples is a regulated process that directly influences the reliability of diagnostic testing. Mishandling a specimen during transit can cause the sample to degrade, leading to inaccurate laboratory results. If a sample is compromised, it may delay treatment, necessitate a recollection, or lead to misdiagnosis. Maintaining the integrity of the collected specimen from the patient’s bedside to the testing laboratory is a requirement for quality healthcare, ensuring the sample conditions remain stable for precise analysis.
Sample Preparation and Stabilization
The initial steps following a blood draw are foundational to preserving the sample’s integrity. Each primary receptacle, typically a blood collection tube, must be clearly and permanently labeled with the patient’s unique identifier, the date, and the time of collection. This labeling ensures complete traceability and prevents misattribution, which can lead to incorrect treatment plans.
For tubes containing anticoagulants, such as EDTA or citrate, the sample must be gently inverted eight to ten times to ensure the additive is fully mixed. Serum tubes, which lack an anticoagulant, must be allowed to clot fully, typically for 10 to 30 minutes, before processing. Failure to allow for complete clotting before centrifugation can result in fibrin strands contaminating the separated serum.
Many tests require separating serum or plasma from cellular components to prevent analyte breakdown. For example, glucose testing samples must be centrifuged within two hours of collection to separate the plasma from red blood cells, which continue to metabolize glucose and lower the measured concentration. Once separated, the serum or plasma must be transferred into a dedicated, properly labeled transfer tube using a pipette, taking care not to disturb the packed cells or the gel barrier. Requirements for additives, clotting time, and separation must align with instructions provided by the testing laboratory and the tube manufacturer.
The Triple Packaging System
Once the sample is stabilized, its physical protection relies on the standardized triple packaging system. This system is mandated for shipping biological substances, ensuring that if one layer fails, subsequent layers prevent leakage and exposure. The innermost component is the primary receptacle—the blood tube or transfer vial containing the specimen. This layer must be leak-proof and securely capped, often with screw caps reinforced with adhesive tape.
The second layer is the secondary packaging, a durable, water-tight container designed to hold one or more primary receptacles. This container must withstand an internal pressure differential of 95 kPa (kilopascals) to prevent rupture during air transport. The space between the primary and secondary containers must contain enough absorbent material to completely soak up the entire volume of liquid if all primary receptacles leak. Acceptable materials include cellulose wadding, cotton balls, or super-absorbent packets.
Finally, the entire assembly is placed within the tertiary, or outer, packaging. This final layer must be rigid, constructed from robust materials like corrugated fiberboard, wood, or plastic. The outer box protects the inner components from physical damage during handling and must pass a 1.2-meter drop test without compromising the contents. This three-tiered structure provides both chemical containment and mechanical protection during transportation.
Maintaining Required Thermal Conditions
Maintaining the correct temperature range throughout transit is essential for preserving sample integrity, as thermal fluctuations can rapidly degrade biological markers. Blood samples generally fall into three thermal categories: ambient (15 to 25 degrees Celsius), refrigerated, or frozen. Ambient temperature is suitable for certain sample types and requires protection from extreme heat or cold, but no cooling elements.
Refrigerated samples require 2 to 8 degrees Celsius, often achieved using insulated containers packed with pre-conditioned gel packs or frozen cold packs. These packs should be placed around the secondary packaging to maintain the cold chain for the expected duration of transit. Wet ice should be avoided, as it can melt and compromise the package’s integrity or expose the sample to excessive moisture.
Frozen samples, often requiring temperatures below -20 or -70 degrees Celsius, require dry ice (solid carbon dioxide). Dry ice sublimates (turns directly into gas) at a rate of approximately 5 to 10 pounds every 24 hours, so sufficient quantity must be included for the full shipping time. Primary receptacles must never come into direct contact with the solid block, as the extreme cold can cause tubes to crack and lead to sample loss. Whole blood specimens should not be shipped with dry ice because the freezing and thawing cycle causes cellular rupture (hemolysis), rendering the sample unacceptable for analysis.
Legal Requirements for Biohazard Shipping
The transportation of blood specimens is governed by international and national regulations that classify them as dangerous goods due to their biohazard risk. Blood samples are typically classified as a Biological Substance, Category B (United Nations number UN 3373). This classification applies to infectious substances that do not meet Category A criteria, meaning they are unlikely to cause permanent disability or life-threatening disease in healthy individuals.
Compliance with regulations from bodies like the International Air Transport Association (IATA) and the Department of Transportation (DOT) is required. The outer packaging must clearly display the diamond-shaped UN 3373 mark, with the proper shipping name “Biological Substance, Category B” printed adjacent in lettering at least six millimeters high. The package must also include the full name and telephone number of a responsible person for emergency contact.
While a full Shipper’s Declaration for Dangerous Goods is not required for UN 3373 shipments, certain documentation is essential for accountability. An itemized list of the package contents must be enclosed between the secondary and outer packaging. The Chain of Custody (COC) form, which documents the transfer of possession from the collector through every handler until it reaches the testing facility, must accompany the shipment to ensure full traceability.