Human platelet lysate — frequently asked questions

Human platelet lysate is a growth factor–rich cell culture supplement derived from human platelets. It is a human-derived alternative to fetal bovine serum (FBS) used to support the expansion of cells in vitro.

hPL is human-derived rather than animal-derived, is rich in native human growth factors, and offers more reproducible, defined performance with fewer ethical and supply concerns than FBS.

Fibrinogen is a clotting protein in platelets that can gel culture media. Depleting it during manufacturing prevents clot formation, so media stays consistent without adding an anticoagulant such as heparin. Every CytoPure™ formulation is fibrinogen-depleted.

Yes. hPL is used as a full replacement for FBS in many workflows. Transitioning generally requires only adjusting the supplement concentration for your cell type, not changing your protocol.

No. Because CytoPure™ is fibrinogen-depleted, supplemental heparin is not required. CytoPure™ XF and GI contain no added heparin; CytoPure™ PLUS includes heparin in the formulation.

CytoPure™ is typically added to culture medium at a final concentration between 2% and 10%. The optimal concentration should be determined for each cell line and application.

All three are fibrinogen-depleted. PLUS includes heparin for routine research. XF is xeno-free with no added heparin. GI is xeno-free, no added heparin, and adds a gamma-irradiation step for additional pathogen risk mitigation. See the comparison.

CytoPure™ ships frozen and should be stored at −20 °C, or at −80 °C for storage beyond 12 months. Thaw in a 37 °C water bath until no ice remains and aliquot to avoid repeated freeze-thaw cycles.

Cloudiness or particulate after thawing is normal and does not affect performance. Filtration is not recommended. Particulates can be reduced by centrifugation for 8 minutes at 2000 × g or brief incubation at 37 °C, if desired.

CytoPure™ is manufactured from human platelet units collected at FDA-licensed, AABB-accredited blood centers in the United States. Multiple donor units are pooled in large batches to minimize lot-to-lot variability.

Each lot is released against defined specifications and ships with a Certificate of Analysis reporting pH (USP <791>), osmolality (USP <785>), total protein (USP <1057>, 4.0–7.0 g/dL), sterility (USP <71>), mycoplasma, endotoxin (USP <85>), cell growth verification, and donor viral testing (21 CFR Part 610).

Cell growth verification is the one worth noting: it is a performance test rather than a composition test. Every lot has to support proliferation of primary human cells before it is released. See CYT-QTS-031 for methods and acceptance criteria, and the example COA for the format.

Viral safety rests on donor eligibility criteria, screening, and infectious disease testing of the source material, together with the regulatory framework governing its collection. Every human platelet unit used in manufacture was approved for human use and tested under 21 CFR Part 610.

As with any product of human origin, no testing regimen can entirely exclude the presence of infectious agents. CytoPure™ should be handled as potentially infectious material using Biosafety Level 2 practices. The full position, including the complete donor testing panel, is in CYT-VSD-009.

No — lot reservation and lot pre-screening are not offered. We would rather say so plainly than take the order and disappoint you later. What we can do is tell you the lot number and send its Certificate of Analysis before you commit, and bulk and standing-order arrangements are available through a quote.

Shelf life is 3 years from date of manufacture when stored at ≤ −20°C; the expiration date is printed on every bottle and on the Certificate of Analysis.

Animal-derived material: CytoPure™ XF and GI are xeno-free — no animal-derived material is used at any stage. CytoPure™ PLUS contains heparin sodium of porcine origin, which is why it is not described as xeno-free. No bovine, ovine or caprine material is used in any product at any stage, which is the basis of the TSE/BSE assessment in CYT-TSE-002.

Cytologics publishes full performance data for primary human mesenchymal stromal cells — bone marrow, adipose and umbilical cord derived. That covers growth curves against a 10% FBS control, doubling time, lot-to-lot consistency across five independent lots, four-passage expansion, ISCT surface marker profile, and trilineage differentiation.

We have also evaluated CytoPure™ in T-cell and NK-cell culture over multi-day culture, assessing viability, cell count and activation — high viability and normal function were observed. Expansion kinetics for those cell types have not been characterized, so we do not publish growth data for them.

For every other cell type we publish the starting concentrations reported in the human platelet lysate literature, with citations, on the Applications page — those are literature values from other preparations, not CytoPure™ performance claims.

No. CytoPure™ is provided for Research Use Only and is not intended for diagnostic procedures, therapeutic use, or administration to humans or animals. It is not qualified as an ancillary material for clinical manufacture.

It is manufactured under a documented quality management system from human platelet units collected at FDA-licensed, AABB-accredited U.S. blood centers, and every lot is released against defined specifications with a lot-specific Certificate of Analysis. The applicable standards are set out in CYT-QTS-031.