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Frequently Asked Questions


Does Elk have a consistent supply of platelets?

Yes, our strong supply partnerships ensure ample Cell Xpand® supply to meet large-scale commercialization needs.


Are platelet donors screened prior to use?

Yes. The human platelet lysates that we use are manufactured from apheresis platelet units sourced from FDA/AABB approved blood centers. Donors have been tested and found to be negative for communicable diseases including HIV I/II Antibody, HIV NAT, HTLV I/II Antibody, Hepatitis B Surface Antigen, Hepatitis B Core Antibody, Hepatitis C Virus Antibody, Hepatitis C NAT, and RPR for Syphilis.


Is heparin already present in the bottle? Do I have to include it?

Heparin is not present in Cell XPand®, and it is not required for use. Porcine heparin prevents clotting due to plasmatic coagulation factors. Since Cell XPand® is processed to deplete fibrinogen, we minimize the possibility of further clotting.


What are freeze/thaw recommendations?

Although multiple freeze/thaw cycles do not harm Cell XPand®

performance, we recommend limiting them to an absolute minimum. If not using the entire volume, upon initial thaw, aliquot into desired volumes and refreeze at -20ºC or -80ºC for long-term storage. 


What are the typical concentrations for different cell types? 

Data demonstrate that Cell XPand® is generally suitable at a lower  concentration than FBS or AB Serum (between 2-10%), since it contains high concentrations of growth factors and cytokines. 


Do you offer a Certificate of Analysis?

All Elk Bioscience products are supplied with a CoA upon purchase, providing all release criteria, data, and information. 


Can we use your products for clinical trials?

Yes. We have a Drug Master File on record with the FDA that is referenceable. Cell XPand® has been used in many clinical trials.


How is Cell XPand® made?

Cell XPand® is made from expired human platelets that were intended for use in humans in hospitals and clinics.They have been tested and approved for human use by the FDA/AABB. 


Why should we choose Elk?

At Elk Bioscience we are dedicated to serving those creating cell based therapies to heal and improve the lives of patients. Cell XPand® performs to improve cell manufacturing process and enhances the probability of successful therapies, while meeting regulatory expectations and offering outstanding quality at the best market price. We offer a consistent, reliable and commercially available hPL, delivered to you when needed the most.

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