These recommendations and procedures apply to the analytical tests performed by the CTQ as part of epidemiological research and population surveys. They deal with the preparation and sending of plasma or serum samples.
When collecting blood, it is important to use the appropriate tubes, as some of them may be contaminated by the analytes you want to measure.
- The most commonly used tubes are:
Tube No Anticoagulant Type Vol. Becton Dickinson (BD) Royal Blue # 368 381 EDTA plasma 6 ml Becton Dickinson (BD) Royal Blue # 368 380 --- serum 6 ml Becton Dickinson (BD) Lavender # 366 643 EDTA plasma 10 ml Becton Dickinson (BD) Lavender # 367 863 EDTA plasma 6 ml Becton Dickinson (BD) Red # 367 815 with activator serum 6 ml Becton Dickinson (BD) Red # 367 895 with activator serum 10 ml Greiner Bio-One Royal Blue # 456 275 Heparin plasma 6 ml
- For those samples that will be frozen, it is recommended to use transfer tubes made of polypropylene with a screw cap (ex. : Sarstedt # 60 550 100).
- The choice of the volume of the sample tube is determined by the analytical requirements and the quantitative analysis method. The methods often require different volumes of samples. Contact us to determine the tubes you will need.
- In order to avoid contaminating your samples, please be careful when handling the material and the samples. Wearing nitrile gloves protects you from infections and also allows to reduce the risk of contaminating the samples.
- Once the sampling is completed, it is important to mix the tube by inversion at least ten times, in order to properly dissolve the anticoagulant. This ensures the integrity of the sample on the long term.
Please watch our video about manually mixing the tube by inversion (duration: 17 sec)
Centrifugation and subdivision
- Centrifuge the sample 10 minutes at 3000 RPM to separate the plasma/serum from the red blood cells.
- Using a polyethylene pipette of 6 mL (Sarstedt # 86 1174), transfer the supernatant to an appropriate tube. You have two options, depending on the nature of the analytes to be measured:
- A polypropylene tube with screw cap (ex. : Sarstedt # 60 550 100)
- A glass vial of 7 ml pre-rinsed with screw cap and PTFE/silicone disc (Supelco # 27341).
- When the sample must be divided in several aliquots (tubes), use a plastic Pasteur pipette.
- The quantitative analysis of metals will require a pre-rinsing of the pipette with 10% nitric acid solution, followed by a rinsing with demineralized water.
Please watch our video about the centrifugation and the subdivision of plasma in aliquots (duration: 58 secs)
If the CTQ receives a partially coagulated sample, or containing micro-clots, it is possible that we will not be able to perform the analysis, and the mention “inadequate sample” will show on the analytical report.
Furthermore, the CTQ recommends to send a volume of plasma/serum higher than the minimum usually required for the quantitative methods, in order to perform a repeat measure or to confirm a high result, for example. It is possible that, in the presence of some low volume pediatric samples, some pre-analytical conditions become difficult to obtain. The CTQ will adjust the analytical strategy with your agreement.
- The serum/plasma are usually kept at 4oC for a few days.
- In order to ensure the integrity of samples for a longer period of time and for an overseas transportation, for example, it is recommended to freeze them at - 20oC.
- For sending overseas, it may be necessary to add dry ice.
Adding a stabilizing or preservative agent to the samples is not usually necessary. Otherwise, the CTQ will inform you.
Establish an exhaustive list
A list of the samples included, on paper, must be joined to the shipment. Furthermore, the CTQ recommends to send a copy of this list by e-mail to the person responsible of projects at the CTQ ([email protected]).
This list must contain the following information:
- The identification of all the samples;
- The dates of sampling and all other relevant information, such as age, place of sampling;
- The contact information of the applicant (address, mail, telephone, etc.).
Proper identification of samples
Each sample must be identified with a self-adhesive label printed with a laser printer, in order to prevent the discolouring of the ink. The label must be resistant to freezing and biological matrices. A barcode identification should be the preferred option.
Choosing the right courier service
For the shipment of the samples, the CTQ recommends a fast, reliable courier service, that ensures a close tracking of the shipments and offers a proof of delivery (ex.: Federal Express, UPS, World Courier, etc.). The shipment of samples for reception the following day is usually difficult and expensive. Provided that all necessary precautions are taken (sufficient amount of refrigerant, etc.), and sending the shipment at the beginning of the week, the samples will arrive to destination in good condition. If the samples are to remain in circulation during the week-end, they must be kept refrigerated by the courier company. Even if this expensive option is available with some specialized carriers, it is better to avoid the transportation of samples during the week-end.
Verify the requirements of cross-border customs
Carefully verify with the courier service all the requirements of the cross-border customs. The courier company is the best suited to inform you about the applicable laws in every country where the samples will transit through.
A few days before the shipping, please send the shipment tracking number to the CTQ by e-mail, in order for the CTQ to be able to quickly take action, should an issue arise during transportation.
How to pack the samples
- Place the samples in order on a rack in the appropriate box;
- Add sufficient absorbent paper in the box, in order to absorb the total amount of your samples in the event of a spill;
- Close the box;
- Place the box in a Ziploc-type bag;
- Place everything in a cooler;
- Fill the empty space with padding brown paper;
- Add the cooling elements;
- Close the cooler;
- Add the list of samples and close the cardboard box;
- Place the sender and receiver labels;
- Add the mention “EXEMPT HUMAN SPECIMENS”;
- Add the dry ice labels if needed;
- Add the commercial invoice for the shipping;
With dry ice inside, the cooler should not be tight, because that increases the risk of explosion.
How to identify the shipment or the cooler
- Place your address as sender;
- Place the receiver’s address:
Laboratoire de toxicologie, Centre de toxicologie / INSPQ
945 avenue Wolfe, 4e étage
Québec, QC, G1V 5B3
- In order to minimize the waiting time at customs, the CTQ recommends to add the mention “EXEMPT HUMAN SPECIMENS” outside the box, and the mentions “EXEMPT HUMAN SPECIMENS, HUMAN SERUM, FOR RESEARCH ONLY, NO COMMERCIAL VALUE” on the commercial invoice.
Please watch our video about the preparation of shipments of plasma samples (duration: 3 min 34 sec)