Serum Resources & FAQs

• Bovine serum is a by-product of the meat industry. Bovine blood may be taken at the time of slaughter, from adult cattle, calves, very young calves or (when cows that are slaughtered are subsequently found to be pregnant) from bovine fetuses.
• Blood is available from bovine fetuses only because a proportion of female animals that are slaughtered for meat for human consumption are found to be pregnant.

• Serum is the amber-colored blood fraction remaining after the natural coagulation of blood; it is typically further refined via centrifugation, which serves to remove remaining blood cells. There are no deletions or additions (including preservatives) allowed.
• Fetal bovine serum (FBS) is the serum derived from blood drawn from a bovine fetus via a closed system of collection in a facility that is approved by the national competent authority.
• Whilst the procedure of making serum may seem to be straightforward, the processing of serum takes place under very tightly controlled conditions. The process has been carefully developed and uses sophisticated facilities and equipment, accompanied by extensive testing. The levels of control and testing are particularly stringent when processed bovine serum is intended for use in the production of medicinal products.

• Fetal bovine serum (FBS) is used as a growth supplement for the in vitro cell culture of eukaryotic/mammalian cells. Animal sera—both bovine and non-bovine sera—are used in cell culture applications with the most widely used being fetal bovine serum.
• FBS contains 1000+ components, including proteins, electrolytes, lipids, carbohydrates, hormones, enzymes, and other undefined constituents. It also contains very low levels of antibodies, allowing for versatility in many different cell culture applications.
• FBS is typically used at a concentration of 5–10% in a basal medium.
• FBS composition is undefined, and therefore can vary from lot-to-lot.

Serum: Serum is the liquid fraction of clotted blood. It is depleted of cells, fibrin and clotting factors. Serum differs from plasma in that anti-coagulant is never added to the blood after collection from the animal.

Fetal Bovine Serum: Semi-processed or raw FBS is obtained from the blood of fetuses of healthy, pre-partum bovine dams subjected to veterinary inspection. Fetal blood is collected aseptically using cardiac puncture. There are no deletions or additions (including preservatives) allowed.

Specialty Fetal Bovine Serum: Semi-processed or sterile filtered FBS subjected to one or more modification processes, e.g. Dialyzed, Charcoal Stripped, Ultra-low IgG, ES Cell, MSC and Exosome-Depleted.

Newborn Calf Serum: Liquid fraction of clotted blood from healthy, slaughtered bovine calves aged less than 20 days, deemed fit for human consumption. No deletions or additions allowed.

Donor Bovine Serum: Liquid fraction of clotted blood from healthy cattle 12 months or older from controlled donor herds with health status confirmed by authorized veterinarians.

Bovine Serum (Adult Bovine or Calf Serum): Liquid fraction of clotted blood from healthy, slaughtered cattle 12 months or older, deemed fit for human consumption by ante- and/or post-mortem inspection.

The ISIA has developed definitions of origin based on international guidelines from the WTO, OIE, USDA, and the EU.

Country of Collection: The country where the animal was slaughtered and blood collected. This is the "origin" shown on the label and required on the CoA and CoO. Collection is considered substantial transformation.

Country of Manufacturing: The country where filtration, bottling, and labeling occur. Listed on the CoA. Not considered substantial transformation.

Country of Further Treatment: Country where the product is treated after sterile filtration (e.g. gamma irradiation, heat inactivation). Not considered substantial transformation.

The Country of Collection can never change for import/export purposes.

9CFR virus testing: Virus panel testing per CFR Title 9, Part 113.53 (c). Detected by fluorescent antibody.

Biochemical and hormone profile: Quantification of biochemical and hormonal (estradiol, insulin, progesterone, testosterone, thyroxine) profiling that may impact cell culture.

BSE status: WOAH-recognized sanitary status of countries/zones. Negligible-risk regions have lesser biosafety risk for import.

EMA virus testing: Virus panel testing per CFR Title 9, Part 113.53 (c). Detected by fluorescent antibody.

Endotoxin testing: Directly related to quality of collection and processing; higher levels indicate more gram-negative bacteria introduction.

Filtration: Triple (0.1 µm) filtration — aseptic process validated to meet the industry standard sterility assurance level of 10⁻³.

Haemoglobin/hemoglobin: Indicator of proper or improper collection and processing of blood and/or serum.

Mycoplasma testing (H-Stain): Direct culture and Hoechst stain — result should be Not Detected.

Origin confirmation: Proprietary fingerprinting technology to confirm FBS origin and eliminate counterfeit product.

Osmolality: Should be similar to culture media to avoid osmotic shock impacting cell viability.

Performance (RGP): Growth promotion assay measuring FBS lot ability to support proliferation of fastidious human diploid fibroblasts.

pH: Serum acts as a buffer in the cell culture system; tested to ensure culture quality and performance.

Total protein: Rich variety of proteins that can impact cultured cells; measured by chemistry panel.

How is FBS Produced and Tested?

• Fetal bovine blood is collected using equipment designed to prevent microbial contamination under carefully monitored procedures.
• The process takes place in a specially constructed area in the abattoir under clean, controlled conditions.
• Aseptically collected fetal blood is refrigerated immediately, allowed to clot, then centrifuged to separate serum from the clot. Serum is kept frozen until thawed immediately prior to further processing.
• Processing of each batch includes: thawing and pooling material; sterile filtration through membrane filters of reducing pore size; re-freezing immediately after filtration.
• Samples are tested to confirm freedom from bacteria and other microorganisms. Extensive biochemical and biological testing are also performed.
• Viruses are not removed by sterile filtration — the batch must be tested for contaminating viruses. The method of choice for viral removal is gamma irradiation. Click here to view articles on gamma irradiation.
• Records are kept linking each process step and test result to each individual batch.
• The customer may perform tests on the batch prior to purchase. The overall testing process may take several months to complete.

Fetal bovine serum (FBS) is a byproduct of the meat industry. No one can influence the amount of FBS available. Drought, high feed prices and high beef demand leads to more available FBS. Milk prices can also impact availability as dairy cows are culled when there is an oversupply of milk. When farmers rebuild their herds, there is less FBS on the market. The price and availability of FBS can be difficult to predict.

Both academic and industrial researchers use FBS in cell culture media for a range of applications, including:

• Vaccine production — Techniques refined in the 1940s–50s led to the first cell culture-based vaccine — polio vaccine, in 1955.
• Biopharmaceuticals — Cell culture combined with recombinant techniques has led to biopharmaceuticals offering important new treatment and diagnostic opportunities.
• Safety testing — Used to test cosmetics and household chemicals, increasingly replacing live animal testing.

• The rules and regulations that processors of bovine serum must respect are complex and change often.
• Some regulations directly affecting finished bovine serum apply to other materials of animal origin as well. They ensure the movement of products between countries does not pose a risk to animal or human health.
• When bovine serum is used in the manufacture of pharmaceuticals, additional rules ensure the material can safely be used in its intended application.

• Export and import of animal by-products necessarily involves collaboration between different national and international regulatory bodies.
• WOAH animal health status information is the basis upon which decisions relating to movement of animal by-products are made.
• Veterinary controls worldwide are often based upon rules established by the USDA and the European Commission — the two largest global markets for animal-derived products.

• Bovine serum has a long and extensive history of safe use in the manufacture of human and veterinary pharmaceutical products.
• Serum destined for use as a raw material in medicinal product manufacture is subject to particularly stringent quality and safety requirements.
• Regulatory bodies involved include: in the USA — USDA, FDA, and United States Pharmacopoeia; in Europe — the European Commission, EDQM, and EMA.
• Scientific advice is also issued by supra-national organizations such as the WHO and the WOAH.

Key precautions taken to significantly reduce possible risks in pharmaceutical/vaccine manufacture:

• All conditions of slaughter, collection, storage, manipulation, processing, treatment, testing, and transport are carefully controlled to minimize contamination risk.
• Bovine blood is only collected in countries with a known, well-monitored and acceptable animal health status, using WOAH published information.
• WOAH-monitored diseases include animal-to-animal transmitted diseases (e.g. foot and mouth disease) and potentially zoonotic diseases.
• Source countries must have authority-licensed abattoirs. Animals must be inspected before slaughter and meat passed as fit for human consumption.
• ISIA member companies have Quality Assurance systems for equipment, facilities, and staff training.
• Fetal bovine and donor serum is often gamma irradiated in specially validated facilities. Click here to learn more.
• All procedures are comprehensively documented, with test results available for every step and every batch produced.
• The ISIA has established a very comprehensive traceability policy ensuring each batch cannot be substituted with unknown material.

"May 19, 2023, Atypical BSE detection does not change the negligible risk status of the United States." Click here for more information.

• BSE ("Mad Cow Disease") has been very much in the spotlight. Because humans are susceptible to BSE, a key question is: what precautions prevent transmission via medicinal products manufactured using bovine serum?
• Guidance focuses on risk minimization. Companies must submit detailed sourcing, collection, and processing information for expert review.
• There is no evidence that BSE has ever been transmitted via a medicinal product and no infectivity has been found in the blood of afflicted cattle.
• Similar diseases called transmissible spongiform encephalopathies (TSEs) are very resistant to chemical and physical treatments that destroy bacteria and viruses. It is not possible to effectively treat bovine serum to inactivate the BSE agent.
• The WOAH monitors BSE incidence globally. Click here to view the WOAH website.
• BSE is a disease of older animals. Source animals for bovine serum must be less than three years old — a cut-off based on scientific consensus.