How to ship clinical samples


This guide outlines the requirements for shipping with FedEx Express. In addition, all shipments must comply with all applicable local, state and federal laws governing packing, marking and labeling. Blood, urine, fluids, and other specimens containing or suspected of containing infectious substances must be shipped according to applicable government, International Air Transport Association (IATA) and International Civil Aviation Organization (ICAO) regulations.

For the purposes of this guide, clinical samples are generally defined as non-infectious human or animal materials including, but not limited to, excreta, secreta, tissue and tissue fluids, blood and FDA-approved pharmaceuticals that are blood products.

Steps for how to ship liquid clinical samples

For liquid clinical samples, you must include four layers of packaging.

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Secure liquid sample in a watertight inner receptacle

watertight receptacles

Use watertight containers for liquid specimens with a positive closure such as a screw-on, snap-on or push-on lid, taped for an additional seal. If you place multiple fragile primary receptacles in a single secondary receptacle, they must be individually wrapped or separated to prevent contact between them.

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Apply absorbent material

absorbent materials

Place absorbent material between the primary and secondary receptacles, using enough material to absorb the entire contents of all primary receptacles. Acceptable absorbent materials include cellulose wadding, cotton balls, super-absorbent packets and paper towels.

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Secure liquid sample in a secondary inner receptacle

secondary receptacles

We recommend using a secondary watertight inner receptacle. Use a watertight sealed plastic bag, plastic canister or screw-cap can.

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Pack liquid sample in outer packaging

Ensure outer packaging is sturdy. Use rigid outer packaging constructed of corrugated fiberboard, wood, metal, plastic, or other equally strong material appropriately sized for the contents. Chipboard, paperboard boxes, paper envelopes, and plastic bags are unacceptable outer packaging. The completed packaging must be of good quality, strong enough to withstand the normal rigors of transportation without loss of contents as a result of vibration, changes in temperature, humidity or pressure.

Include a marking on the package that properly identifies the shipment as “Exempt Human Specimen” or “Exempt Animal Specimen” as appropriate to comply with current IATA and ICAO regulations. If you prefer, package markings may be in the form of a label.

Steps for how to ship dry clinical samples

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1. Secure dry sample in the envelope

Place dried samples, including but not limited to hair, swabs, or dried blood, into a sealed paper or plastic envelope.

Note: If the dried sample is placed in a receptacle with a liquid preservative, then follow the packaging guidelines for shipping liquid samples. 

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2. Package and seal dry clinical sample

Ship all dry clinical samples inside a Tyvek® or flexible® plastic envelope, padded envelope, paperboard envelope or paper mailer measuring 6" x 8" or larger.

If samples are cushioned on glass or plastic slides, package in a sturdy outer container to prevent breakage and puncturing.

The FedEx® Clinical Pak may be used to ship any dry clinical sample.

Include a marking on the package that properly identifies the shipment as “Exempt Human Specimen” or “Exempt Animal Specimen” as appropriate to comply with current IATA and ICAO regulations. If you prefer, package markings may be in the form of a label.

FedEx Clinical Paks

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FedEx Clinical Boxes
FedEx Cold Clinic Paks

FedEx clinical packaging options

For your convenience, we offer the FedEx Small Clinical Pak, FedEx Large Clinical Pak, FedEx® Medium Clinical Box, and the FedEx® Large Clinical Box as packaging options for exempt clinical-sample shipments. We recommend the FedEx Clinical Paks for use when the sturdy outer packaging of your properly packaged shipment is smaller than the minimum acceptable package size 7" x 4" x 2" (17.78 cm x 10.16 cm x 5.08 cm).

To help ensure the timely delivery of your shipment and the safety of shipments exposed to yours, our clinical paks and boxes help your clinical shipments stand apart from other shipments.

To order FedEx clinical packaging, go to or call 1.800.GoFedEx 1.800.463.3339.

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FedEx clinical packaging options for purchase

FedEx Cold Shipping Box

We offer five cold shipping boxes as part of the FedEx Temp-Assure® portfolio of products for purchase. These boxes can be used as outer packaging to ship temperature-sensitive clinical samples via FedEx Express services.

Each box includes a chilling unit activated by the shipper and placed in the box with the shipment. The unit continuously evaporates small amounts of water at low pressure, keeping the shipment at 2°C to 8°C for up to 48 or 96 hours,* depending on the packaging option chosen.

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Packaging guidelines

The FedEx Large Clinical and the FedEx Small Clinical Paks are overwraps primarily designed for easy identification and to handle smaller completed packages.

  • The FedEx Large Clinical and the FedEx Small Clinical Paks can only be used to ship clinical samples. If you need an overpack for shipments of Biological Substance, Category B (UN 3373) materials, use the FedEx UN 3373 Pak.
  • Liquid blood and liquid blood products must always be placed in sturdy outer packaging before being placed in a FedEx Large Clinical or a FedEx Small Clinical Pak.
  • The FedEx Large Clinical and the FedEx Small Clinical Paks can be used to ship dried samples when packaged according to the dried sample guidelines.
  • The FedEx Medium Clinical Box, the FedEx Large Clinical Box, and the following Temp-Assure cold shipping boxes can be used to ship clinical samples: Small Cold Box (2–8°) Standard Duration (48 Hours); Medium Cold Box (2–8°) Standard Duration (48 Hours); Medium Cold Box (2–8°) Extended Duration (96 Hours); Large Cold Box (2–8°) Standard Duration (48 Hours); and Large Cold Box (2–8°) Extended Duration (96 Hours). Other FedEx packaging is not acceptable as outer containers for clinical samples.
  • Shipments marked or labeled as hazard class 6.2 (infectious materials) and shipments containing dry ice cannot be shipped in FedEx packaging.

If you have questions about whether your shipments require a biohazard label, consult the Occupational Safety and Health Administration (OSHA) for the applicable regulations.

NOTICE: This packaging information is provided to FedEx customers to help reduce loss or damage due to improper packaging. It is NOT intended to be a comprehensive guide for packaging items we accept for transit. We make no warranties, expressed or implied, regarding this information. Proper packaging is the sole responsibility of the shipper. For more information and comprehensive guidelines, contact the FedEx Dangerous Goods/Hazardous Materials Hotline at 1.800.GoFedEx 1.800.463.3339; press “81” or say “dangerous goods,” then press “4” for the next available dangerous goods agent. (Outside the U.S., request to speak to a dangerous goods representative.) Refer to the current FedEx Service Guide for terms, conditions, and limitations applicable to FedEx® delivery services.