When you work in the medical, clinical, or scientific sector, you know that time and reliability dictate everything. Whether it involves critical tissue for research or urgent diagnostics, shipping medical samples across borders is no everyday logistical task. You are dealing with strict international legislation, temperature sensitivity, and complex customs procedures. In this article, we dive deep into the world of shipping UN3373 and show you exactly how to get your shipments to their destination safely, legally, and without unnecessary delays.
Chantal has been writing about logistics topics for almost two decades and has worked for major international carriers.
If you need to internationally ship blood samples, tissue cultures, or other patient materials, they almost always fall under the umbrella of dangerous goods. More specifically: they are classified as biological substances category B, bearing the corresponding UN number UN3373.
According to the international guidelines set by the World Health Organization (WHO) and the IATA, a Category B substance is an infectious material that, upon exposure, is not capable of causing permanent disability or a life-threatening disease in otherwise healthy humans or animals. Examples include:
Diagnostic specimens (blood, urine, saliva).
Excised tissue or organs for research.
Certain viral or bacterial cultures that do not fall under the stricter Category A (UN2814/UN2900).
Because these materials pose a potential risk, they are subject to specific regulations. This means you must comply with strict packaging and documentation requirements, including determining the correct HS code for customs declaration.
You cannot simply put a medical sample in a standard cardboard box. To allow a UN3373 shipment to fly safely, you must follow the P650 packaging instruction (Triple Packaging). This method ensures that any potential leaks do not endanger the outside world, the couriers, or the aircraft.
The triple packaging system works as follows:
Primary receptacle: A watertight, leak-proof tube or vial (e.g., a blood tube) containing the specimen.
Secondary packaging: A second leak-proof, durable packaging. Crucially, there must be enough absorbent material between the primary and secondary packaging to absorb the entire contents of the primary receptacle(s) in case of breakage.
Outer packaging: A sturdy external box of high quality. The diamond-shaped UN3373 label ("Biological Substance, Category B") must be clearly visible on this outer layer.
A delay at the border can render a medical sample useless. Therefore, perfect preparation of your paperwork is essential. When shipping outside the EU, you need a correctly completed commercial invoice or pro forma invoice.
Be extremely specific on your invoice. Do not just use the term "Medical samples." State exactly what it is, include the correct HS code, and add that it concerns UN3373 material with no commercial value (if applicable for testing purposes). If you want to know exactly how this works for specific countries, check out our comprehensive guide on customs duty clearance.
For the B2B market, such as laboratories and clinics, standard postal services are simply not an option. You need speed and predictability. By choosing express delivey through a reliable logistics partner, you guarantee that your shipment is prioritized within the network.
Through the ParcelParcel platform, you can effortlessly compare the best carriers specializing in express delivery. We not only ensure you have access to the fastest transit times, but our logistics specialists also proactively check whether your pro forma invoice and UN3373 labels meet all requirements. This minimizes the risk of delays and safeguards the integrity of your medical shipment.
Biological substances category B (UN3373) are infectious materials that do not cause life-threatening diseases in healthy humans or animals. This primarily includes diagnostic samples such as blood, urine, tissue, and saliva sent for research, testing, or medical analysis.
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A UN3373 package must feature a diamond-shaped label (minimum 50 mm x 50 mm) on the outside containing the text "UN3373". Directly adjacent to this mark, the proper shipping name "Biological Substance, Category B" must be clearly and legibly displayed. Also, ensure that the name and telephone number of a responsible contact person are on the outside of the box.
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Yes, you can ship blood samples and other medical samples conditioned with dry ice to keep them at the required temperature. Note: dry ice is classified as a dangerous good (UN1845). You must therefore affix a Class 9 (Miscellaneous) dry ice label to the outer packaging and state the net weight of the dry ice on the box and the shipping documents. The packaging must allow CO2 gas to escape to prevent explosions from pressure buildup.
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For shipments outside the EU, you need an Air Waybill and a detailed Commercial Invoice or Pro Forma Invoice. On the invoice, you must describe the contents exactly, state the value (often "$1.00 for customs purposes only" for test material), the country of origin, and the correct customs commodity code (HS code).
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With express delivey via premium carriers, shipments within Europe can often be delivered the next business day (frequently before 09:00 or 12:00 AM). To major business hubs in the United States or Asia, an express shipment takes an average of 1 to 3 business days, depending on local customs clearance.
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You can instantly check the shipping costs through our rate calculator. Enter the weight, dimensions, and destination country of your shipment, and you will see all available shipping options along with their respective delivery times. The calculator can be used to compare shipping rates for both export and import shipments.
If you need help calculating a shipping rate, watch the video below. Click on the 
button to play the video and the 
icon to view the video in fullscreen.
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Shipping costs are calculated based on dimensions (LxWxH in cm), weight (in kg), and the destination country. Both the actual weight (as shown on the scale) and the volumetric weight are considered.
The volumetric weight is the weight calculated based on the space your shipment occupies in the plane. The higher of the two weights (volumetric or actual weight) is used to calculate the shipping rate. You don't need to calculate this yourself; our calculator does it for you.
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You can use the discount code PP10 for 10% discount on the transportation costs of your first shipment. You can apply the discount code during the checkout process (instructions).
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Whether additional costs apply depends on whether your shipment stays within the European Union or is sent to/from a country outside the European Union. Below, you can see the additional costs for each situation.
Within the European Union
If, for example, you send a shipment from the Netherlands to Italy (within the EU), there will be an additional 21% VAT on the shipping costs.
Furthermore, if your shipment stays within the European Union, you won't have to deal with any import duties or customs clearance fees because your shipment doesn't go through customs. Please note that the European Union is not the same as Europe.
View here all the countries that are part of the European Union. For example, Switzerland is part of Europe but not part of the European Union.
Outside the European Union
If, for example, you send a shipment from the Netherlands to the United States, there will be no VAT (0%) applied to the displayed shipping rates.
However, there might be import duties levied by customs in the destination country if you send a shipment to/from a country outside the European Union. Typically, customs costs are charged to the recipient. This is known as Delivered At Place (DAP) in logistics terminology.
Customs is a government agency that levies import duties in certain cases to protect the local market. As a company, you can also ship using Delivered Duty Paid (DDP), which means any customs costs will be charged to you as the sender.
If you have any questions about this topic, feel free to contact us. Additionally, you can read everything about import duties, VAT, and the customs clearance process in this blog.
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A customs invoice is a form where all the goods you want to ship are specified. This invoice includes an English description of the goods, along with their corresponding value and weight.
The contents of your shipment must be specified per type of product you're sending to avoid delays at customs. A customs invoice is always prepared in quadruplicate in accordance with customs guidelines.
When is a customs invoice required?
A customs invoice is only required for shipments to/from countries outside the European Union (e.g., Netherlands - United States). If your shipment stays within the European Union (e.g., Netherlands - Italy), your shipment will not go through customs, and therefore, a customs invoice is not required.
Additionally, document shipments are not subject to customs, so if you're sending a document to a country within/outside the European Union, no customs invoice is needed.
Please note that not all goods can be shipped to every country. You can find a list of goods that cannot be sent via ParcelParcel on this page.
Do I need to create a customs invoice myself?
If you're sending a shipment to/from a country outside the European Union, it's mandatory to include a customs invoice with the shipment. We provide free support in creating a customs invoice.
You can easily generate a customs invoice through our shipping platform. The customs invoice will be automatically generated based on the content you specified during your booking.
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You can import just as easily as export via ParcelParcel.
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You can find a list of goods that cannot be shipped via ParcelParcel on this page.
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