The amount of a (5z7e)-(3s)-262626272727-hexafluoro-910-seco-5710(19)16-cholestatetraen-23-yne-325-diol when measured in blood serum. The trait is Ontology of Biological Attributes term OBA_2045202 (level of 26,26,26,27,27,27-hexafluoro-25-hydroxy-16,17,23,23,24,24-hexadehydrovitamin D3 in blood serum). Also known as: blood serum (5z7e)-(3s)-262626272727-hexafluoro-910-seco-5710(19)16-cholestatetraen-23-yne-325-diol amount.