Obtaining blood serum

Technique to obtain blood serum

Published on 19/3/2022 by Jose Cancino ‐ 3 min

Protocols Lab Equipment

Technique

To obtain blood serum, a centrifuge with adapters for blood collection tubes (CT) will be used, in which CTs with coagulation activators (red colored) can be placed.

These tubes are coated with silicone inside and contain tiny silica particles that accelerate the coagulation process.

👉 There are CTs with separator gel (yellow color) that act similar to the red tubes, but simplify serum extraction by using polymers with inert characteristics that form a barrier between the serum and the clot during the centrifugation process.

Obtaining the sample

The procedure starts with the blood collection and identification of the sample with a unique code that lacks any personal information of the patient. The day and exact time of blood collection will be recorded.

Immediately after extraction, the tube should be gently inverted several times to promote coagulation (4 times maximum), then the tube will be kept in an upright position. The sample must be transported to the lab within 45 minutes.

Sample processing

In the lab, the clot formation will be verified otherwise it is advisable to wait for the clot formation (15-30 minutes after collecting the sample). The sample will be processed within the first two hours after extraction and will be discarded if it is not processed within 24 hours.

The TC will be centrifugued at 1600 G (3,600 RPM for rotors with a radius of 112mm) for 15 minutes. At the end of the centrifugation, a clear and transparent supernatant will be visible, with a slight yellowish coloration corresponding to blood serum.

👉 For CT with gel separator, the use of a centrifuge with a swing-out rotor instead of a centrifuge with an angular rotor allows obtaining a more stable gel barrier. (2)

Separate the supernatant with a Pasteur pipette taking care not to touch the interface gel if yellow CTs are used. Aliquot 0.5 ml of the blood serum in each of the microcentrifuge tubes or in cryovials (4 to 6), which should be properly labeled and identified. (3,4)

Serum preservation

The serum samples will be kept in the refrigerator until use, it is important to verify the correct sealing of the microcentrifuge tubes. If the serum is not used in the next 2 or 3 days, it should be frozen in cryovials at -80ºC for one week.

References

Distribuciones Científicas NESSLER. Tubo para extracción con gel separador de suero. Madrid: Nessler [Internet]. [cited 19 mar 2022]. Available from: https://www.dcnessler.com/fungibles-pdfs/tubo-bd-gel-separador.pdf
García Sánchez M, Mayorga L, Díaz T, Martín I, Giraldo Castellanos P, Civeira Murillo F, et al. Obtención, Procesado Y Almacenaje de Muestras de Suero. Madrid: Red Biobancos. [Internet]. 2011 [cited 19 mar 2022]. Available from: https://redbiobancos.es/wp-content/uploads/pnt-suero.pdf
Guerin JS, Murray DW, McGrath MM, Yuille MA, McPartlin JM, Doran PP. Molecular medicine ireland guidelines for standardized biobanking. Biopreserv Biobank [Internet]. 2010 [cited 20 mar 2022];8(1):3-63. Available from: https://doi.org/10.1089/bio.2010.8101
Campbell LD, Astrin JJ, DeSouza Y, Giri J, Patel AA, Rawley-Payne M, Rush A, Sieffert N. The 2018 Revision of the ISBER Best Practices: Summary of Changes and the Editorial Team’s Development Process. Biopreserv Biobank [Internet]. 2018 [cited 20 mar 2022];16(1):3-6. Available from: https://doi.org/10.1089/bio.2018.0001

Obtaining blood serum

Technique #

References #

Technique

References