Human Serum Off-the-Clot (OTC) — Maximum Native Growth Factors
Off-the-clot (OTC) serum is produced from whole blood that is allowed to clot naturally without anticoagulants. When blood clots, platelets activate and degranulate — releasing PDGF, EGF, TGF-β, IGF-1, FGF, and other growth factors directly into the serum. This process generates the highest and most diverse growth factor spectrum of any serum preparation method.
In contrast, plasma-derived serum is made from plasma that has been separated before clotting. Because platelets are removed before the clotting step, platelet degranulation does not occur — resulting in a product with significantly lower growth factor content. For cell expansion applications where maximum proliferative support is required, OTC serum is the correct choice.
OTC vs Plasma-Derived Serum
| Parameter | Off-the-Clot (OTC) | Plasma-Derived (PD) |
|---|---|---|
| Platelet degranulation | ✅ Occurs — full growth factor release | ❌ Does not occur — platelets removed before clotting |
| PDGF, EGF, TGF-β, IGF-1 | ✅ High — maximum native levels | Lower — growth factor-depleted |
| Lot size | Smaller — requires more donors per lot | Larger — plasma pooling allows bigger lots |
| Lot-to-lot variability | Slightly higher | ✅ Lower — larger donor pools |
| Best for | R&D, process development, cell expansion | Large-scale manufacturing, production consistency |
| Processing options | HI, GI, or native (cryopreserved) | HI or GI standard |
Specifications
| Parameter | Specification |
|---|---|
| Collection method | Off-the-clot — whole blood, natural coagulation, no anticoagulants |
| Blood type | Mixed (various) or specify AB |
| Donor pool | Mixed gender or specify male-only |
| Processing | Heat inactivated (56°C/30 min), gamma irradiated, or native cryopreserved |
| Filtration | 0.2 µm sterile filtered |
| Origin | EU and/or US |
| Viral testing | HIV-1/2, HBsAg, HCV, HIV-1 RNA, HCV RNA, HBV DNA |
| Volumes | 100 mL, 500 mL | Bulk on request |
| Storage | −20 °C |
Complete Human Serum Portfolio
| Product | Blood Type | Donor | Processing | Primary Use | Order |
|---|---|---|---|---|---|
| Human Serum | Mixed | Mixed | HI or GI | General cell culture, diagnostics | Shop → |
| Human Serum, Male | Mixed | Male only | HI or GI | Hormone-controlled cell culture | Shop → |
| Human Serum, Type AB | AB | Mixed | HI or GI | Immunoassays, diagnostics | Shop → |
| Human Serum Type AB, Male | AB | Male only | HI or GI | Cell therapy R&D, immune assays | Shop → |
| Human Serum Off-the-Clot | Mixed | Mixed | OTC | Growth factor-rich cell culture | Shop → |
| Human Serum Type AB, Off-the-Clot | AB | Mixed | OTC | Universal donor, growth factor-rich | Shop → |
| Human Serum Type AB, Male OTC | AB | Male only | OTC | CAR-T, NK cells, ATMP — gold standard | Shop → |
Contact: info@seamlessbio.de | +49 851 37932226