Paving the Way for the Future of Blood Transfusions

Our novel blood bag system was subject of an award-winning clinical study

August 17, 2023

Since the 1950s, DEHP (di-ethyl-hexyl-phthalate) has been used in blood bag systems to ensure the bags are soft and flexible, and that the blood maintains its quality. However, the European Commission has decided to sunset DEHP in the second half of this decade.

Caring for life and our patients’ health is Fresenius Kabi’s utmost priority. Dr. Ulja Schmidt is part of the team which has developed a blood bag system with a red cell storage bag made of PVC/BTHC (butyryl trihexyl citrate) material. Dr. Christie Vermeulen of Sanquin Blood Bank in The Netherlands conducted a study of this blood bag system, which includes reformulated additive solution. The study focused on the efficacy of the system in maintaining required quality of the components.

In her paper Clinical and in vitro evaluation of red blood cells collected and stored in a non-DEHP plasticized bag system, Dr. Vermeulen has demonstrated that Fresenius Kabi’s redesigned material and additive solution are a viable alternative to systems made with DEHP. For her outstanding research, Dr. Vermeulen received the Vox Sanguinis Best Paper Prize.

Dr. Christie Vermeulen (front) and Dr. Ulja Schmidt (3rd from left) with colleagues at the ISBT congress in Goetheburg
Dr. Christie Vermeulen (front) and Dr. Ulja Schmidt (3rd from left) with colleagues at the ISBT congress in Goetheburg

Interview with Dr. Ulja Schmidt, marketing lead for whole blood processing, on why the recently launched blood bag system not made with DEHP addresses market needs.

Would you summarize the importance of the clinical study which Christie Vermeulen addresses in her article?

In her paper, Christie presents the results of laboratory studies on the processing and storage of red blood cells in our redeveloped blood storage system. She reports the results on the adverse events after transfusion of 1,650 red cell concentrates. These red cell concentrates (RCC) were prepared in blood donation systems not made with DEHP. The rate of adverse events after transfusion was consistent with historical norms for blood bag systems made with DEHP*. It is unusual and valuable to have both in-vitro and in-vivo results on a blood bag system.

What conclusion did the study reach, and what insights were gained from the study?

The conclusion is that after storage, the quality and shelf-life of red cells is similar in the redesigned blood bag system compared to the ones currently in use. Although larger studies are needed to confirm this finding, this initial study shows no increase in the rate of transfusion reactions.

DEHP has already been replaced in many medical devices. Why is it still the main softener used for whole blood collection systems?

In addition to providing appropriate physical properties for blood bags, DEHP also stabilizes the membranes of red cells and therefore has a positive effect on the shelf-life of red cells. With the PVC/BTHC material and redeveloped storage solution, we were able to replicate the positive characteristics of DEHP in storage systems.

Why is it important to look for alternatives?

The European Chemical Agency (ECHA) has decided to sunset the use of DEHP in medical devices in the second half of this decade. Many suppliers of components made with DEHP have already stopped their production because of the stringent requirements.

What happens if you simply remove DEHP from the blood bag systems? Would you explain the challenges of finding an alternative?

Removing the softener would lead to a very brittle material unsuitable for blood storage. Until now, alternative plasticizers didn't perform as well as DEHP to allow an extended storage time of red blood cells under current processing conditions. Red blood cells would be disrupted and release hemoglobin which may have a negative health impact on patients.
The combination of our PVC/BTHC material and a reformulated storage solution manages to protect red cells by an alternative pathway. The quality of red cells provided to patients is similar to those stored in systems made with DEHP.

What is the impact of this development on the health care field and Fresenius Kabi?

Patients depend on a steady, stable supply of red cell concentrates. Maintaining a shelf-life of 42 days reduces wasted blood components. For us at Fresenius Kabi, this blood bag system is another way we demonstrate our caring for life mission.


* C. Vermeulen et al, Vox Sanguinis. 2022; 117: 1163-1170.