{"id":2903,"date":"2026-08-22T15:48:36","date_gmt":"2026-08-22T14:48:36","guid":{"rendered":"https:\/\/seamlessbio.de\/?page_id=2903"},"modified":"2026-08-23T00:57:37","modified_gmt":"2026-08-22T23:57:37","slug":"what-is-off-the-clot-serum","status":"publish","type":"page","link":"https:\/\/seamlessbio.de\/de\/what-is-off-the-clot-serum\/","title":{"rendered":"What is Off-the-Clot (OTC) Serum"},"content":{"rendered":"
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Quick Definition<\/p>\n

What is Off-the-Clot (OTC) Serum?:<\/strong> Off-the-clot (OTC) serum is human serum produced by allowing whole blood to clot naturally at room temperature without anticoagulant. During natural clotting, platelets fully activate and degranulate, releasing growth factors (PDGF, EGF, TGF-\u03b2) into the serum. OTC serum therefore has higher growth factor content than standard plasma-derived serum.<\/p>\n<\/div>\n\n

OTC serum vs standard serum \u2014 what is the difference?<\/h2>\n

Standard human serum is produced from plasma collected with anticoagulant \u2014 clotting is then triggered artificially with calcium chloride. Platelets remain largely intact and do not fully degranulate, so their intracellular growth factor content stays trapped. The result is a serum with a more controlled, reproducible protein profile but lower mitogenic activity.<\/p>\n

In OTC serum, natural clotting causes complete platelet activation. All intracellular growth factors are released, producing a significantly richer growth factor environment \u2014 better for cell proliferation, worse for assay consistency.<\/p>\n\n

Key applications for OTC serum<\/h2>\n