Alyssa Master Ph.D. Senior Manager, Science and Applications Nucleus Biologics

Four Steps to Ensuring Greater Quality & Consistency in FBS and Scientific Research

Cell culture and in vitro models are important in helping scientists elucidate cell responses to various therapies and facilitate scientific discovery. Lack of reproducibility of scientific experiments is a pervasive issue that affects cell culture work due to the plethora of uncontrollable components used in these systems. Reproducibility and overall success is predicated by consistently high quality components that enable continued scientific breakthroughs.

Serum is a complex organic solution of proteins, growth factors, amino acids, lipids, carbohydrates,  vitamins, and other components to promote growth and maintenance of adherent or suspension cells. Fetal Bovine Serum (FBS) is the most commonly used serum supplement because of its rich growth factor, protein, and macromolecule levels. FBS is a byproduct of the meat industry, using blood fraction after coagulation from which red blood cells have been removed. While serum-free and non-animal-derived (xeno-free) media can be used in some systems, they do not provide a suitable environment for many cell lines, and often require tradeoffs such as higher expense and slower growth rates.

Vastly different grades of FBS are available on the market. With critical parameters at stake such as reproducibility and cell viability, dependable quality is essential. Every variable matters and inconsistency in quality can result in failed experiments, as assistant professor and cancer biologist Matthew Sikora, Ph.D., University of Colorado Anschutz Medical Campus, found when his laboratory was stalled for several months due to sequential batches of serum failing initial screens.

“We estimated the cost of the failed experiments at over $45,000 in just personnel and consumables. We think that unrecognized variations in serum might explain why we could not get consistent results,” said Dr. Sikora. “Researchers who don’t test their serum could run into trouble and risk expensive delays.”

What criteria are important for researchers to assess when gauging the the quality of their FBS? 


Perhaps the biggest risk to scientists when it comes to poor quality FBS is compromised purity, which can lead to reduced efficacy and lack of reproducibility in cell culture experiments. Many sellers of FBS source raw materials under multiple, short-term supply agreements from various locations to help lower costs. They pool the product in an attempt to dilute the effects of any one source. The end result is inconsistent quality and fluctuations in availability and price.

The concept of traceability was brought about because this mechanism of sourcing made it almost impossible to find out what region FBS originated from. In response to this issue, the International Serum Industry Association (ISIA) has implemented an industry standard for supply chain traceability which is crucial to assuring the quality, safety, and reproducibility of FBS lots. Some companies provide chemical analysis indicating the statistical probability of country of origin. Perhaps the best approach is to have traceability back to the animal, to ensure the product origin. This can be further simplified with single-source and single-origin lots.

Does the FBS supplier maintain records of traceability from origin throughout the supply chain? Do they retain documentation supporting all stages of processing, transportation, and commercial transactions? Can they show traceability to an exclusive source to ensure reproducibility and low-viral risk? These are all important questions to ask when considering purchasing FBS.

The Geographical Risk Assessment (GBR) qualitatively evaluates the likelihood that an animal within a country or region is infected with diseases such as BSE (Bovine Spongiform Encephalopathy, or mad cow disease). This method strongly depends on the surveillance system of the World Organization for Animal Health (OIE) which classifies the BSE risk in each country or region through the Terrestrial Animal Health Code, or Terrestrial Code. The OIE assesses countries’ veterinarian services, ability to diagnosis diseases, awareness of symptoms, and other factors as a well-rounded approach to solving and avoiding the spread of BSE.

New Zealand and Australia have received a GBR level 1, meaning they currently are, and are likely to remain, BSE and Foot and Mouth Disease (FMD) free. Both are known throughout the world as having the lowest viral risk. Due to protected environments, as well as strict agricultural regulations and entry requirements in these countries (and both being islands, lowering risk), animals are less likely to be exposed to diseases that affect herds elsewhere. This is especially useful for sensitive cell lines and experiments that require consistency. For scientists, this means less time spent on repeating failed experiments or testing new lots for consistency.

Consistency In Product and Manufacturing

The Current Good Manufacturing Practice (cGMP) regulations, enforced by the U.S. Food and Drug Administration (FDA), put in place systems to help to ensure proper design, monitoring, and control of manufacturing processes and facilities. Purchasing from suppliers that adhere to cGMP guidelines can help to reduce risks from sterile filtration, pooling products, and mislabeling.

Other important factors to ensure lot-to-lot consistency include common herd environment, and food source and quality control testing procedures. Proper collection is fundamental to maintaining the natural growth-promoting properties of raw fetal blood and achieving consistent, superior performance of the final FBS product. Researchers should look for suppliers that have been inspected and certified by internationally recognized bodies, such as the FDA, USDA, AQIS, and other industry associations, to ensure product safety.

Stable Pricing

The cost of FBS can fluctuate drastically based on many variables. As a byproduct of the meat industry, FBS production is inherently influenced by everything from weather and food supply, to economic conditions and herd size. If adventitious viruses infect a particular source, there will be a reduction in cattle and, thus, in FBS supply. Additionally, when it is expensive to feed cows due to drought, farmers may send livestock to market or slaughter, resulting in reduction in herd sizes. After a herd reduction, farmers hold on to cattle to rebuild their herds.

Finally, the global demand for FBS is increasing. There is approximately 600,000 L of FBS produced annually with less than 200,000 L being cGMP grade—a requirement of most industrial-scale companies.  With the demand from large pharmaceutical companies on the rise, the price of FBS continues to rise as well. With FBS pricing fluctuating drastically, it is important to find a supplier that can deliver consistent and traceable lots, guarantee supply needs, and offer some degree of protection from price volatility.

Characterization/Product Testing

Users should look to suppliers that regularly test products for biochemical, hormonal, viral, and functional aspects (including presence of bacteria, viruses, and other microorganisms) to assure a clean, characterized product. Quality control testing should be performed to ensure that serum products consistently conform to regulations and meet specifications.


Though often portrayed as a commodity, FBS and other serums have the potential to greatly impact the quality and reproducibility of cell-culture work. The role of FBS should be elevated, given the significant impact its purity—or lack thereof—has on vital experiments. With demand for FBS increasing across the globe and many factors contributing to quality, price, and supply, being able to know what to look for in the origin and manufacture of this critical component has the potential to improve experiments and advancements that could potentially save human lives.

Alyssa Master, Ph.D. ([email protected]), is senior manager, science and applications at Nucleus Biologics.

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